Jose,
I am not familiar with the specific attenuators you show but I suspect that
they are hermetically sealed units, similar to the HET switch. The HET
switch appears to be the 5061-4820. The attenuator appears to be 5061-4822
and 5061-4823. It looks like 5061-4819 is the Reverse Power detector.
However, the interconnects are not very clear on the picture (though the
picture is of good quality).
The problem I have seen is that these hard lines get 'bent' center
conductors. I would carefully remove each of them from the HET switch on
down the line, carefully inspect the center conductor and the 'socket' it
mates with (light and magnifiers needed) to make sure that there is not
something simple going on.
Opening these sealed units could be a problem but I have heard of folks
doing that.
Good luck.
Joe
toggle quoted message
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-----Original Message----- From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...] On Behalf Of Jose V. Gavila Sent: Tuesday, January 01, 2013 4:24 PM To: hp_agilent_equipment@... Subject: Re: [hp_agilent_equipment] HP-8657A question Hi Tom, Oh, one other thing. I have seen this problem caused by a bad coax
connection to one of the modules. They are compression fittings to
the outer conductor and if over tightened, damage will occur. Thanks for the hint! So, if that is the case, what would you do to fix it?. I mean, is it a good idea to disconnect them to check?. I have no clue of how the mating is made... is there any online picture of them? Regards, JOSE -- 73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN) AGVradio Personal WEB
|
The large nut tightens down on a collet that clamps the coax. If it is over tightened, it will crush the outer shield and deform it. Maybe even short to the inner conductor? Are any connections loose? If you wiggle them while observing the output, you might find something. You might open one to see how it is arranged.
Good luck,
Tom
toggle quoted message
Show quoted text
----- Original Message -----
From: Jose V. Gavila
To: hp_agilent_equipment@...
Sent: Tuesday, January 01, 2013 5:24 PM
Subject: Re: [hp_agilent_equipment] HP-8657A question
Hi Tom,
> Oh, one other thing. I have seen this problem caused by a bad coax
> connection to one of the modules. They are compression fittings to
> the outer conductor and if over tightened, damage will occur.
Thanks for the hint!
So, if that is the case, what would you do to fix it?. I mean, is it a
good idea to disconnect them to check?. I have no clue of how the mating
is made... is there any online picture of them?
Regards,
JOSE
--
73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN)
AGVradio
Personal WEB
|
At 04:07 PM 1/1/2013, you wrote Snip
So, if I am correct, my SAFT LX-1634 3.0 V battery represents the 'old' 2.9
volt battery although my battery does not state what the chemistry of the
battery is. Therefore, if I can find an exact replacement of the battery,
chemistry and all, I would prefer to just replace the battery rather than
place a new battery and resistors.
Snip some more From the SAFT website: Lithium-manganese dioxide (Li-MnO2) : LX series This is NLA from SAFT, but, you now know the chemistry. 73 Glenn WB4UIV
|
Hmm, I think your right. The watchdog circuit appears to compare the battery voltage with the power supply voltage to see if the power on sequence has obtained sufficient voltage before applying power to the NVRAM control circuit in a sense taking the battery offline, or so it would appear. I'm a bit confused by how the battery voltage is being distributed. It's not going back out the transistors and if I'm not mistaken that zenor diode CR636 shouldn't conduct until it hits it's threshold voltage. There is one label of "NVVCC" however that's not designated as a tap. I must be missing something. CR635 is clearly in place to keep the battery from being charged. I guess the voltage drop doesn't matter to them.
The resistors I don't believe will need to be changed. I'm sure they did to meet their design specs, but I doubt it would matter in 99.99% of the cases. The comparator is still going to do what it was designed for, just at a slightly different threshold. The entire circuit seams like a bit of overkill in my opinion. But hey it works.
Also looking at this circuit it would appear the NVVCC could end up being 4 volts or so once everything is turned on. Figuring the voltage drop in U637D, chances are it would end up higher due to the very low current and those caps. So that being said I don't even see an issue with a 3.6 volt battery vs a 3.0 volt battery. I don't have my meter yet to measure any of this..so I'm just speculating. I guess I could toss it in spice if I was motivated.
Thanks,
Jeff
toggle quoted message
Show quoted text
On 1/1/2013 2:07 PM, J. L. Trantham wrote:
Steve, Jeff, and all,
According to the manual, the 'New Main Controller' was installed starting at
SN 2538A02954 and later. The Assembly Number, 03457-665xx, etc., is under
the power transformer and difficult to see but there. Also, regarding the
'new' battery and 'new' resistors, the manual states 'the new parts are on
assembly A11, ERC no. 2850 and greater' which I interpret to mean SN
2850Axxxxx and greater.
The 'New Main Controller' is easy to identify by just looking at where the
battery is located. Looking from the front of the meter, with the top cover
off and the 'shield' over the main controller off, the 'old' controller had
the battery to the left side of the board, near the left side of the meter,
about half way back from the front while the 'new' main controller has the
battery on the right side of the board, near the center of the meter, about
one fourth of the way back from the front.
So, if I am correct, my SAFT LX-1634 3.0 V battery represents the 'old' 2.9
volt battery although my battery does not state what the chemistry of the
battery is. Therefore, if I can find an exact replacement of the battery,
chemistry and all, I would prefer to just replace the battery rather than
place a new battery and resistors.
Also, the PCB is manufactured so as to provide mounting for a battery with
one positive and one negative pin as well as a battery with one positive and
two negative pins. Therefore, there may be some other options.
Has anyone found any information specifically about the SAFT LX-1634
battery?
Interestingly, the same SAFT LX-1634 battery is used in the 3478A. I
replaced the 3478A battery with a BR-2/3A several months ago with no
detectable problems so far but the battery backup circuitry is much simpler
than the 3457A. Also, of note, the BR-2/3A reads 3.397 VDC.
As best I can tell, the only role for R644 and R645 is during the Power On
Reset and the Low Power Reset. It would appear that the Low Power Reset is
the only issue of concern. The 'old' components set a level of about 2.99
VDC at the + input of U636A while the 'new' components set a level of about
3.46 VDC at the + input of U636A when the UNREG +5 VDC supply drops to 7
VDC. If no changes in resistors were made, the same 3.46 VDC would occur
when the UNREG +5 VDC supply dropped to about 8.1 VDC. I measure 11.18 VDC
on my UNREG +5 VDC supply.
Therefore, I can't see a compelling reason to change the resistors. The
Power On Reset is released later and the Low Power Reset is applied earlier
if all you do is replace the SAFT LX-1634 with a BR-2/3A. Would this be a
problem? Am I missing something?
Thanks for all the help in 2012 and Happy 2013.
Joe
-----Original Message-----
From: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of Steve
Sent: Monday, December 31, 2012 7:34 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
Joe and all,
I will pop the covers off mine again and have a look at the A1 board
revision number and resistor values. Regarding battery voltage, I noticed a
couple of web sites state that their lithium batteries are "3.6 v nominal,
3.4 volt operating" I assume that's at their rated current so HP may have
been stating operating voltage. I can't imagine that maintaining cal
constants would draw much current though.
Steve
On Dec 31, 2012, at 6:25 PM, "J. L. Trantham" <jltran@... <mailto:jltran%40att.net>
<mailto:jltran%40att.net> > wrote:
Steve, Jeff, and all,
My 2703Axxxxx 3457A also has the SAFT LX 1634, Lithium 3.0V, battery and it
measures 3.032 VDC. Likewise, I can not see a date code on the battery,
even after removing the A1 Board and looking as far under the battery as
possible.
My A1 Board is 03457-665xx, REV A, 2703. According to the manual, this is
the 'New Main Controller'. However, on my board, A11R644 is a 17.4 K
resistor and A11R645 is a 13 K resistor which represents the 'old' resistors
and matches the schematic. The 'new' resistors would be 13 K and 12.7 K
respectively, according to the parts list and 'Changes'. The 'old' battery
is listed as a 'Battery 2.9V .9A-HR Li/S-Diox W-Flex', according to the
Agilent website. Likewise, the Agilent website lists the 'new' battery as
a
'Battery 3V 1.2A-HR Lithium Poly Carbon'. Only the manual parts list lists
the 'new' battery as 3.4 V.
In addition, I don't think I have ever seen a 3.4 V Lithium battery.
So, the question is, when it comes time to replace the battery, what should
be used?
Joe
-----Original Message-----
From: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Steve Krull
Sent: Monday, December 31, 2012 11:20 AM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
Joe and all,
I just had a quick look inside my 3457A again. Mine has the 3.0 volt
lithium battery, SAFT LX-1634. Obsolete at Agilent, as is the newer
battery. Google was no help either. Mine measures 3.03 volts and there's
no evidence of corrosion so that's good. I couldn't see a date code on
it; probably on the underneath side. I've replaced batteries by
paralleling the existing connections with an appropriate power supply
and then unsoldering the old battery with an isolated-tip iron and
soldering in the new battery. I've also carefully soldered a new battery
in parallel with the old and then clipped out the old one. No problems
with lost data so far.
I'm not sure how the cal numbers increment. I'll have to experiment with
that sometime. Right now I need to repair the 1349D display in my 8757A
so I can get on with a sweeper plug in project, so the volt-nuttery is
on hold for awhile.
Happy New Year to all!
Steve
On 12/30/2012 5:34 PM, J. L. Trantham wrote:
Steve,
Thanks for the data. Mine is also 2703A prefix with REV?:6,0 and
CALNUM?:98. Not a multiple of 34. Would be interesting to see what the
CALNUM increments by after an Agilent CAL.
I, too, need to look at the battery condition. I have not looked
at the
manual regarding replacing the battery. Has anyone done that without
losing
the CAL Constants?
Joe
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of Steve
Sent: Sunday, December 30, 2012 4:14 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
It would be interesting to see if a newer rev is out there. My 3457A
is s.n.
prefix 2703, with rev 6,0 and option 0, CALNUM=34. I wonder if that's a
default number for anything less than a full cal at Agilent? The last
calibration was at least 6 years ago and performed by what was then
Boeing
Military Airplane Company's metrology lab. I need to open it up and
check
the battery condition.
Steve
On Dec 29, 2012, at 8:08 PM, "J. L. Trantham" <jltran@...
<mailto:jltran%40att.net>
<mailto:jltran%40att.net>
<mailto:jltran%40att.net>
<mailto:jltran%40att.net>
<mailto:jltran%40att.net> > wrote:
If the 'SELF TEST OK' message appears, there is no need to make any
'adjustments'. Just do the 'front panel CAL' if needed.
As I said, I would check it out, assume it is the best instrument in
your
collection, send it to Agilent for CAL and see what you get.
I would appreciate knowing what 'REV?' and 'OPT?' says when you
get a
chance. 'CALNUM?' would be interesting as well.
In the 3458A, the firmware is in an EPROM (6 EPROM's for the older units)
and can be removed, a socket placed, and easily upgraded by purchasing the
latest pre-programmed EPROM (or EPROM's for the older units) from Agilent.
The only problem is they have a $50 minimum for this $18 part
for the
later
units.
My wife thinks I am going to appear on an episode of 'Hoarders'.
Joe
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
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<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Jeff
Machesky
Sent: Saturday, December 29, 2012 8:01 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
Wow, lots of replies all of a sudden. I'm already prepping the wife for
the $200 + price tag of calibration. Funny how when I was single I would
have about $800 in cash in my wallet at all times and now I beg
for 20
bucks, Hmm. Sad part is I make about 4 times the money. In any event
I've not received to much feedback on the "Self Test OK" message the
seller had posted. Any comments? I'm too much of a skeptic when it comes
to eBay purchases. It's just a convenient place to purchase such
goods.
Any feedback would be appreciated as to possible pitfalls regarding this
device. I like to prep for issues rather then build myself up for
failure. What do they say...it's better to be pleasantly surprised
then
let down.
Thanks,
Jeff
On 12/29/2012 5:40 PM, J. L. Trantham wrote:
According to the manual, there are only two 'adjustments' that can
be
made
on a 3457A, Input Offset Amplifier adjustment and AC Converter
Frequency
Response, both needed only if there is a 'HARDWARE ERR' failure
message
after 'TEST' is selected and then only if it is a specific
'AUXERR' or
16 or
256 is seen. Otherwise, all the calibrations are done from the
front
panel
with specific inputs from the front panel.
The CALNUM? is incremented by 'several digits' with a 'complete
calibration', one for each calibration point entered, per the
manual.
Interestingly, when I sent my two 3458A's to Agilent for
calibration,
the
CALNUM incremented by only 1. However, when I calibrated one
of them
before
sending it to Agilent, (since I lost the data in the DALLAS CALRAM
chip that
I was removing) the CALNUM went from 1 to something like 34 or
something. I
don't recall. It seems that if you have the appropriate
software to
run the
complete calibration protocol, it only increments by '1'
instead of
by
all
the data points entered. Such software exists for the 3457A but I
have
never seen it available 'on theBay'. I suspect Agilent would have
that
software and equipment to do that calibration and, thus, an
Agilent
calibration may only increment the CALNUM? by 1.
When getting an Agilent calibration of the 3458A, you get 'As
Received' and
'As Completed' data. Very helpful to me in that the only two
points
my
'House CAL' of the one 3458A failed were the two 'midrange' AC
Voltage
values. All else 'PASSED'.
I agree with Dave. If it's HP/Agilent, I prefer Agilent to do the
CAL.
If
it's Solartron, I prefer AMETEK (Solartron), etc.
I believe that having some 'basic' professionally calibrated
instruments
(DMM's, Noise Sources, Power Sensors, Frequency Standards (unless
you
have a
GPSDO, CS Standard, etc.) etc.), that you can then use as
'transfer
standards' to do your own 'in house' calibration of other
instruments,
is
very important if you want to set up a reliable workshop.
Of course, you will also need a 'stable' source of the various
signals
that
you will use to be 'measured' by the various 'DUT's', such as
resistance,
voltage, current, frequency, etc. The 3458A is relatively easy to
calibrate, requiring only 10.000000 VDC, 10000.000 ohms, and
some AC
voltage
at various frequencies, IIRC. I have never CAL'd a 3457A but the
3478A
is a
multi-step process.
This whole thing can become very 'addictive'. Be careful.
Joe
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of
David
Kirkby
Sent: Saturday, December 29, 2012 5:53 PM
To: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
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<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
On 29 December 2012 20:01, Jeff Machesky <jeff@...
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com> > wrote:
Thanks Dave, I actually have watched those videos. Bit drawn
out
like
most of his videos..but still good. Too much detail is not
always
a
bad
thing. I thought the bit showing the noise on the DVM was a bit silly
when
it
was connected to a DC power supply.
As for the 3457A, if it works I plan on getting it calibrated by
Agilent
within the year. From what I understand it's about a $200 US
investment.
The meter was last calibrated in '98, so I'll be curious to see
how
accurate it is when I get it. I think the calibration service you chose might dictate
whether you
get data about the condition when sent.
When I send mine in for cal, I'd like to know what was out and by
how
much. But I'm not going to pay extra for a calibration service
that
provides that. As far as I'm concerned, if Agilent calibrate it,
then
it is OK. For me personally, it makes no difference whatsoever
if it
has ISO, NIST or whatever calibration. But I'd prefer Agilent to
someone else.
I have calibration certificate here for an Agilent VNA calibration
kit. It was done by a calibration house in the USA. But from
what I
can gather from reading the documentation, the equipment to
calibrate
them is not available commerically. So it makes me wonder how
a lab
can calibrate a cal kit, when the equipment to do it can't be
bought.
I suspect there is a fairly cosy realationship between some test
equipment dealers and calibration facilities.
I plan on purchasing some
voltage references from the well known site as a basic test
of the
3457A. I may even calibrate it based on those references if it's
way
out
and later getting it NIST traceable calibrated. I don't know if there are pots in there you can adjust with a
trimmer,
or if it is all done electronically. You might find it is
impossible
to calibrate yourself.
I never had any reason to look inside mine.
Dave
------------------------------------
Yahoo! Groups Links
|
Hi Tom, Oh, one other thing. I have seen this problem caused by a bad coax
connection to one of the modules. They are compression fittings to
the outer conductor and if over tightened, damage will occur. Thanks for the hint! So, if that is the case, what would you do to fix it?. I mean, is it a good idea to disconnect them to check?. I have no clue of how the mating is made... is there any online picture of them? Regards, JOSE -- 73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN) AGVradio Personal WEB
|
Re: HP 8970B firmware v2800+ wanted
Christian,
I just checked the firmware on a late version (prefix 3811U) 8970B, standard version (1.6 GHz) and it's Rev 02844. It's possible that this was the last revision of the firmware.
Another 8970B with Opt. 020, which was built around the same time and also carries prefix 3811U has Rev. 01224.
Vladan
|
Oh, one other thing. I have seen this problem caused by a bad coax connection to one of the modules. They are compression fittings to the outer conductor and if over tightened, damage will occur.
Tom
toggle quoted message
Show quoted text
----- Original Message -----
From: Jose V. Gavila
To: hp_agilent_equipment@...
Sent: Tuesday, January 01, 2013 4:59 PM
Subject: Re: [hp_agilent_equipment] HP-8657A question
Hello Joe,
> I suspect it could be either. My 8657A is silent but my 8657B 'clicks'
> every 5 dB and has a mechanical attenuator.
>
> Do you have a picture of the attenuator?
I have uploaded one to:
Thanks!
JOSE
> -----Original Message-----
> From: hp_agilent_equipment@...
> [mailto:hp_agilent_equipment@...] On Behalf Of Jose V. Gavila
> Sent: Tuesday, January 01, 2013 1:41 PM
> To: HP-Agilent Equipment
> Subject: [hp_agilent_equipment] HP-8657A question
>
> Hi all,
>
> I wish you have a nice 2013!
>
> Well, I am working on an 8657A which has no output. So far, following
> Service Manual (SM) troubleshooting guidance, I have found that there is
> signal output from the A6 assembly. So it goes to the attenuator
> assembly and vanishes.
>
> I have a simple question: do the attenuaotrs on this unit generate any
> mechanical noise or are they some kind of electronic switches?
>
> I am following the tests on the SM (SS7) and there is so far a
> difference on a control signal, but it would mean just a wrong
> attenuation setting, but not a fully missing signal.
>
> Any hint will be welcomed!. It is my very first 8657A :-)
>
> Regards,
>
> JOSE
>
--
73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN)
AGVradio
Personal WEB
|
That is the electronic version, no clicks.
toggle quoted message
Show quoted text
----- Original Message -----
From: Jose V. Gavila
To: hp_agilent_equipment@...
Sent: Tuesday, January 01, 2013 4:59 PM
Subject: Re: [hp_agilent_equipment] HP-8657A question
Hello Joe,
> I suspect it could be either. My 8657A is silent but my 8657B 'clicks'
> every 5 dB and has a mechanical attenuator.
>
> Do you have a picture of the attenuator?
I have uploaded one to:
Thanks!
JOSE
> -----Original Message-----
> From: hp_agilent_equipment@...
> [mailto:hp_agilent_equipment@...] On Behalf Of Jose V. Gavila
> Sent: Tuesday, January 01, 2013 1:41 PM
> To: HP-Agilent Equipment
> Subject: [hp_agilent_equipment] HP-8657A question
>
> Hi all,
>
> I wish you have a nice 2013!
>
> Well, I am working on an 8657A which has no output. So far, following
> Service Manual (SM) troubleshooting guidance, I have found that there is
> signal output from the A6 assembly. So it goes to the attenuator
> assembly and vanishes.
>
> I have a simple question: do the attenuaotrs on this unit generate any
> mechanical noise or are they some kind of electronic switches?
>
> I am following the tests on the SM (SS7) and there is so far a
> difference on a control signal, but it would mean just a wrong
> attenuation setting, but not a fully missing signal.
>
> Any hint will be welcomed!. It is my very first 8657A :-)
>
> Regards,
>
> JOSE
>
--
73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN)
AGVradio
Personal WEB
|
Hello Joe, I suspect it could be either. My 8657A is silent but my 8657B 'clicks'
every 5 dB and has a mechanical attenuator.
Do you have a picture of the attenuator? I have uploaded one to: Thanks! JOSE -----Original Message-----
From: hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...] On Behalf Of Jose V. Gavila
Sent: Tuesday, January 01, 2013 1:41 PM
To: HP-Agilent Equipment
Subject: [hp_agilent_equipment] HP-8657A question
Hi all,
I wish you have a nice 2013!
Well, I am working on an 8657A which has no output. So far, following
Service Manual (SM) troubleshooting guidance, I have found that there is
signal output from the A6 assembly. So it goes to the attenuator
assembly and vanishes.
I have a simple question: do the attenuaotrs on this unit generate any
mechanical noise or are they some kind of electronic switches?
I am following the tests on the SM (SS7) and there is so far a
difference on a control signal, but it would mean just a wrong
attenuation setting, but not a fully missing signal.
Any hint will be welcomed!. It is my very first 8657A :-)
Regards,
JOSE
-- 73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN) AGVradio Personal WEB
|
Hi,
One way to do this is to use a PLL chip, like the ADF41020, as the microwave divider. That chip has around -20dBm sensitivity at 10GHz, so you may not need an amplifier ahead of it.
However, you are left with a couple of problems. First, you have to program the chip on every power cycle. For that you can use a small microprocessor, like a PIC. Programming isn't very hard. Second, you need to get the divided down signal to your counter. You program the chip so the divided RF appears on the MUX-OUT pin and buffer the signal with a single gate like an NC7SZ00.
It should be obvious you are not going to get a divide by 10 with this circuit. But "for free" you can prescale by 100 or 1000, which may actually be better, since the signal can then be sent to the baseband counter input. Warning, the divided down signal will probably not be a square wave, but a low duty ratio pulse train.
Regardless of how you do the division, you still need to take care of intput protection. That is a significant engineering project all by itself. If you don't need a lot of input sensitivity, I would suggest putting a 15dB or 20dB attenuator ahead of the divider and see if it can survive.
Good luck,
Lew
toggle quoted message
Show quoted text
--- In hp_agilent_equipment@..., "Erick Schumacher" <wb6kcn@...> wrote:
Hi Folks
Anybody have any advice on getting a decade divider to go in front of a 5385
counter so I can measure frequencies around X band. Divide by 8 is not
acceptable. Clugey is acceptable as long as it is cheap.
Eric
|
Re: Oscilloscopes - analog but with digital capability?
Another problem with random sampling as applied to a sampling oscilloscope and not a storage oscilloscope is that the sampling strobe kickout can corrupt the trigger pickoff causing the display near the trigger point to be distorted. The Tektronix 7T11A manual briefly mentions this issue on page 3-17 but I do not remember if they discussed it further elsewhere: "Random sampling permits display of the leading edge, or any other part, of the input signal as shown in Figure 3-13. This is possible even when observing fast-rise, short duration pulses, and when using either internal or external trigger sources (EXT modes of triggering give better results in Random Sampling)." That issue threw me off for a while when I was first learning to use random sampling. Before I started, I suspected there should be some sort of interaction between the strobe and internal trigger but when I saw distortion exactly where I expected, I thought that was too perfect and something else must be wrong. The distortion is actually useful in some cases where it can identify the exact trigger edge among many on the display. On Tue, 01 Jan 2013 20:37:00 -0000, "Ed Breya" <edbreya@...> wrote: Actually, sequential sampling presents a faster and fuller display, but needs a vertical delay line to be able to see the front edge of fast steps that are widely spaced (low rep-rate). Random sampling provides this without the delay line, but it is more complicated - there are always tradeoffs.
In reality, all oscilloscopes - including analog - are actually "sampling" the signal intermittently, and only for a certain amount of time. They provide short glimpses of the time domain signal, but are blind to it much of the time. When we have a properly triggered analog waveform display on screen, that is made by repeatedly scanning (sampling, of a sort) multiple waves that we trust are virtually identical from one to the next. The trigger system tells us when to look, the sweep system determines for how long, and the screen phosphor saves the information. It's an equivalent-time system that converts the signal frequency down to where our vision can see it.
Ed
--- In hp_agilent_equipment@..., "J. Forster" <jfor@...> wrote:
Chuck,
The random sampling is intentional and is done to reduce the artifacts of
precisely spaced samples.
I think the 3T77A was the first of Tek's attempts. I clearly remember that
one of the 3 Series sampling sweeps was labeled that way.
-John
================
David wrote:
There are many ways to get a waveform using sampling. All of those
that sample waveforms that are higher bandwidth than the sampling rate
are storing only small parts of many, many, repetitions of the signal
under test. In the case of the 7D20, and the 7854, you may be looking
at snippets of hundreds of repetitions of that signal, just to get a
look
at a single copy. In the days of old, these were called sampling
oscilloscopes. My old Tektronix catalogs always refer to them as digitizers or
digital storage oscilloscopes. The term sampling was always
associated with instruments that had actual sampling front ends. It doesn't matter what they call it, if it can't store the whole
waveform in one shot, it is a sampling scope, just as sure as the
old N, 1SXX, 7SXX, etc. plugins were. The prime difference is the
old type N, 1SXX, and 7Sxx plugins used the screen's phosphor, in
combination with the refresh rate, to "store" the sampled bits long
enough for you to see the full waveform. The 7D20, and 7854 use
digital storage bins, filled in a fairly chaotic way, to store the
sampled bits for view. If you have ever watched a 7854 store a
400MHz sine wave using its 50K sampling rate, you know what I mean.
If you have it set to display the stored bits as they come in, you
will see dots randomly appear on the screen (like snowflakes) as
the waveform is generated in the digital memory.
I never picked up a 7D20 because it lacks peak detection but the slow
waveform regeneration rate of my 2230 has only rarely been a problem. I use a 7854, or a 7D20, quite a lot... but only in the single shot
mode. I usually only need storage to handle things that are slower
than my visual refresh rate.
-Chuck Harris
------------------------------------
Yahoo! Groups Links
|
Steve, Jeff, and all,
According to the manual, the 'New Main Controller' was installed starting at
SN 2538A02954 and later. The Assembly Number, 03457-665xx, etc., is under
the power transformer and difficult to see but there. Also, regarding the
'new' battery and 'new' resistors, the manual states 'the new parts are on
assembly A11, ERC no. 2850 and greater' which I interpret to mean SN
2850Axxxxx and greater.
The 'New Main Controller' is easy to identify by just looking at where the
battery is located. Looking from the front of the meter, with the top cover
off and the 'shield' over the main controller off, the 'old' controller had
the battery to the left side of the board, near the left side of the meter,
about half way back from the front while the 'new' main controller has the
battery on the right side of the board, near the center of the meter, about
one fourth of the way back from the front.
So, if I am correct, my SAFT LX-1634 3.0 V battery represents the 'old' 2.9
volt battery although my battery does not state what the chemistry of the
battery is. Therefore, if I can find an exact replacement of the battery,
chemistry and all, I would prefer to just replace the battery rather than
place a new battery and resistors.
Also, the PCB is manufactured so as to provide mounting for a battery with
one positive and one negative pin as well as a battery with one positive and
two negative pins. Therefore, there may be some other options.
Has anyone found any information specifically about the SAFT LX-1634
battery?
Interestingly, the same SAFT LX-1634 battery is used in the 3478A. I
replaced the 3478A battery with a BR-2/3A several months ago with no
detectable problems so far but the battery backup circuitry is much simpler
than the 3457A. Also, of note, the BR-2/3A reads 3.397 VDC.
As best I can tell, the only role for R644 and R645 is during the Power On
Reset and the Low Power Reset. It would appear that the Low Power Reset is
the only issue of concern. The 'old' components set a level of about 2.99
VDC at the + input of U636A while the 'new' components set a level of about
3.46 VDC at the + input of U636A when the UNREG +5 VDC supply drops to 7
VDC. If no changes in resistors were made, the same 3.46 VDC would occur
when the UNREG +5 VDC supply dropped to about 8.1 VDC. I measure 11.18 VDC
on my UNREG +5 VDC supply.
Therefore, I can't see a compelling reason to change the resistors. The
Power On Reset is released later and the Low Power Reset is applied earlier
if all you do is replace the SAFT LX-1634 with a BR-2/3A. Would this be a
problem? Am I missing something?
Thanks for all the help in 2012 and Happy 2013.
Joe
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Show quoted text
-----Original Message----- From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...] On Behalf Of Steve Sent: Monday, December 31, 2012 7:34 PM To: hp_agilent_equipment@... Subject: Re: [hp_agilent_equipment] 3457a on the way Joe and all, I will pop the covers off mine again and have a look at the A1 board revision number and resistor values. Regarding battery voltage, I noticed a couple of web sites state that their lithium batteries are "3.6 v nominal, 3.4 volt operating" I assume that's at their rated current so HP may have been stating operating voltage. I can't imagine that maintaining cal constants would draw much current though. Steve On Dec 31, 2012, at 6:25 PM, "J. L. Trantham" <jltran@... <mailto:jltran%40att.net> > wrote: Steve, Jeff, and all,
My 2703Axxxxx 3457A also has the SAFT LX 1634, Lithium 3.0V, battery and it measures 3.032 VDC. Likewise, I can not see a date code on the battery,
even after removing the A1 Board and looking as far under the battery as
possible.
My A1 Board is 03457-665xx, REV A, 2703. According to the manual, this is
the 'New Main Controller'. However, on my board, A11R644 is a 17.4 K
resistor and A11R645 is a 13 K resistor which represents the 'old' resistors and matches the schematic. The 'new' resistors would be 13 K and 12.7 K
respectively, according to the parts list and 'Changes'. The 'old' battery
is listed as a 'Battery 2.9V .9A-HR Li/S-Diox W-Flex', according to the
Agilent website. Likewise, the Agilent website lists the 'new' battery as a 'Battery 3V 1.2A-HR Lithium Poly Carbon'. Only the manual parts list lists
the 'new' battery as 3.4 V.
In addition, I don't think I have ever seen a 3.4 V Lithium battery.
So, the question is, when it comes time to replace the battery, what should be used?
Joe
-----Original Message-----
From: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> [mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Steve Krull Sent: Monday, December 31, 2012 11:20 AM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> Subject: Re: [hp_agilent_equipment] 3457a on the way
Joe and all,
I just had a quick look inside my 3457A again. Mine has the 3.0 volt
lithium battery, SAFT LX-1634. Obsolete at Agilent, as is the newer
battery. Google was no help either. Mine measures 3.03 volts and there's
no evidence of corrosion so that's good. I couldn't see a date code on
it; probably on the underneath side. I've replaced batteries by
paralleling the existing connections with an appropriate power supply
and then unsoldering the old battery with an isolated-tip iron and
soldering in the new battery. I've also carefully soldered a new battery
in parallel with the old and then clipped out the old one. No problems
with lost data so far.
I'm not sure how the cal numbers increment. I'll have to experiment with
that sometime. Right now I need to repair the 1349D display in my 8757A
so I can get on with a sweeper plug in project, so the volt-nuttery is
on hold for awhile.
Happy New Year to all!
Steve
On 12/30/2012 5:34 PM, J. L. Trantham wrote:
Steve,
Thanks for the data. Mine is also 2703A prefix with REV?:6,0 and
CALNUM?:98. Not a multiple of 34. Would be interesting to see what the
CALNUM increments by after an Agilent CAL.
I, too, need to look at the battery condition. I have not looked at the
manual regarding replacing the battery. Has anyone done that without
losing
the CAL Constants?
Joe
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of Steve
Sent: Sunday, December 30, 2012 4:14 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
It would be interesting to see if a newer rev is out there. My 3457A
is s.n.
prefix 2703, with rev 6,0 and option 0, CALNUM=34. I wonder if that's a
default number for anything less than a full cal at Agilent? The last
calibration was at least 6 years ago and performed by what was then Boeing Military Airplane Company's metrology lab. I need to open it up and
check the battery condition.
Steve
On Dec 29, 2012, at 8:08 PM, "J. L. Trantham" <jltran@...
<mailto:jltran%40att.net> <mailto:jltran%40att.net>
<mailto:jltran%40att.net>
<mailto:jltran%40att.net> > wrote:
If the 'SELF TEST OK' message appears, there is no need to make any
'adjustments'. Just do the 'front panel CAL' if needed.
As I said, I would check it out, assume it is the best instrument in your
collection, send it to Agilent for CAL and see what you get.
I would appreciate knowing what 'REV?' and 'OPT?' says when you get a
chance. 'CALNUM?' would be interesting as well.
In the 3458A, the firmware is in an EPROM (6 EPROM's for the older units)
and can be removed, a socket placed, and easily upgraded by purchasing the
latest pre-programmed EPROM (or EPROM's for the older units) from Agilent.
The only problem is they have a $50 minimum for this $18 part for the later
units.
My wife thinks I am going to appear on an episode of 'Hoarders'.
Joe
-----Original Message-----
From: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com> ] On Behalf Of Jeff
Machesky
Sent: Saturday, December 29, 2012 8:01 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
Wow, lots of replies all of a sudden. I'm already prepping the wife for the $200 + price tag of calibration. Funny how when I was single I would
have about $800 in cash in my wallet at all times and now I beg for 20
bucks, Hmm. Sad part is I make about 4 times the money. In any event
I've not received to much feedback on the "Self Test OK" message the
seller had posted. Any comments? I'm too much of a skeptic when it comes
to eBay purchases. It's just a convenient place to purchase such
goods. Any feedback would be appreciated as to possible pitfalls regarding this
device. I like to prep for issues rather then build myself up for
failure. What do they say...it's better to be pleasantly surprised
then let down.
Thanks,
Jeff
On 12/29/2012 5:40 PM, J. L. Trantham wrote:
According to the manual, there are only two 'adjustments' that can
be made
on a 3457A, Input Offset Amplifier adjustment and AC Converter
Frequency
Response, both needed only if there is a 'HARDWARE ERR' failure
message
after 'TEST' is selected and then only if it is a specific
'AUXERR' or
16 or
256 is seen. Otherwise, all the calibrations are done from the front
panel
with specific inputs from the front panel.
The CALNUM? is incremented by 'several digits' with a 'complete
calibration', one for each calibration point entered, per the
manual. Interestingly, when I sent my two 3458A's to Agilent for
calibration, the
CALNUM incremented by only 1. However, when I calibrated one of them
before
sending it to Agilent, (since I lost the data in the DALLAS CALRAM
chip that
I was removing) the CALNUM went from 1 to something like 34 or
something. I
don't recall. It seems that if you have the appropriate software to
run the
complete calibration protocol, it only increments by '1' instead of
by all
the data points entered. Such software exists for the 3457A but I
have never seen it available 'on theBay'. I suspect Agilent would have
that software and equipment to do that calibration and, thus, an Agilent
calibration may only increment the CALNUM? by 1.
When getting an Agilent calibration of the 3458A, you get 'As
Received' and
'As Completed' data. Very helpful to me in that the only two points
my 'House CAL' of the one 3458A failed were the two 'midrange' AC
Voltage values. All else 'PASSED'.
I agree with Dave. If it's HP/Agilent, I prefer Agilent to do the
CAL. If
it's Solartron, I prefer AMETEK (Solartron), etc.
I believe that having some 'basic' professionally calibrated
instruments
(DMM's, Noise Sources, Power Sensors, Frequency Standards (unless
you have a
GPSDO, CS Standard, etc.) etc.), that you can then use as 'transfer
standards' to do your own 'in house' calibration of other
instruments, is
very important if you want to set up a reliable workshop.
Of course, you will also need a 'stable' source of the various
signals
that
you will use to be 'measured' by the various 'DUT's', such as
resistance,
voltage, current, frequency, etc. The 3458A is relatively easy to
calibrate, requiring only 10.000000 VDC, 10000.000 ohms, and some AC
voltage
at various frequencies, IIRC. I have never CAL'd a 3457A but the
3478A
is a
multi-step process.
This whole thing can become very 'addictive'. Be careful.
Joe
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of David
Kirkby
Sent: Saturday, December 29, 2012 5:53 PM
To: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com> <mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457a on the way
On 29 December 2012 20:01, Jeff Machesky <jeff@...
<mailto:jeff%40codebest.com> <mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com>
<mailto:jeff%40codebest.com> > wrote:
Thanks Dave, I actually have watched those videos. Bit drawn out
like
most of his videos..but still good. Too much detail is not always
a bad
thing. I thought the bit showing the noise on the DVM was a bit silly when
it was connected to a DC power supply.
As for the 3457A, if it works I plan on getting it calibrated by
Agilent
within the year. From what I understand it's about a $200 US
investment.
The meter was last calibrated in '98, so I'll be curious to see
how accurate it is when I get it. I think the calibration service you chose might dictate whether you
get data about the condition when sent.
When I send mine in for cal, I'd like to know what was out and by
how much. But I'm not going to pay extra for a calibration service that
provides that. As far as I'm concerned, if Agilent calibrate it,
then it is OK. For me personally, it makes no difference whatsoever if it
has ISO, NIST or whatever calibration. But I'd prefer Agilent to
someone else.
I have calibration certificate here for an Agilent VNA calibration
kit. It was done by a calibration house in the USA. But from what I
can gather from reading the documentation, the equipment to
calibrate them is not available commerically. So it makes me wonder how a lab
can calibrate a cal kit, when the equipment to do it can't be
bought.
I suspect there is a fairly cosy realationship between some test
equipment dealers and calibration facilities.
I plan on purchasing some
voltage references from the well known site as a basic test of the
3457A. I may even calibrate it based on those references if it's
way out
and later getting it NIST traceable calibrated. I don't know if there are pots in there you can adjust with a
trimmer, or if it is all done electronically. You might find it is impossible
to calibrate yourself.
I never had any reason to look inside mine.
Dave
------------------------------------
Yahoo! Groups Links
|
I suspect it could be either. My 8657A is silent but my 8657B 'clicks'
every 5 dB and has a mechanical attenuator.
Do you have a picture of the attenuator?
Joe
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-----Original Message-----
From: hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...] On Behalf Of Jose V. Gavila
Sent: Tuesday, January 01, 2013 1:41 PM
To: HP-Agilent Equipment
Subject: [hp_agilent_equipment] HP-8657A question
Hi all,
I wish you have a nice 2013!
Well, I am working on an 8657A which has no output. So far, following
Service Manual (SM) troubleshooting guidance, I have found that there is
signal output from the A6 assembly. So it goes to the attenuator
assembly and vanishes.
I have a simple question: do the attenuaotrs on this unit generate any
mechanical noise or are they some kind of electronic switches?
I am following the tests on the SM (SS7) and there is so far a
difference on a control signal, but it would mean just a wrong
attenuation setting, but not a fully missing signal.
Any hint will be welcomed!. It is my very first 8657A :-)
Regards,
JOSE
--
73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN)
AGVradio
Personal WEB
|
Re: Oscilloscopes - analog but with digital capability?
Actually, sequential sampling presents a faster and fuller display, but needs a vertical delay line to be able to see the front edge of fast steps that are widely spaced (low rep-rate). Random sampling provides this without the delay line, but it is more complicated - there are always tradeoffs.
In reality, all oscilloscopes - including analog - are actually "sampling" the signal intermittently, and only for a certain amount of time. They provide short glimpses of the time domain signal, but are blind to it much of the time. When we have a properly triggered analog waveform display on screen, that is made by repeatedly scanning (sampling, of a sort) multiple waves that we trust are virtually identical from one to the next. The trigger system tells us when to look, the sweep system determines for how long, and the screen phosphor saves the information. It's an equivalent-time system that converts the signal frequency down to where our vision can see it.
Ed
toggle quoted message
Show quoted text
--- In hp_agilent_equipment@..., "J. Forster" <jfor@...> wrote:
Chuck,
The random sampling is intentional and is done to reduce the artifacts of
precisely spaced samples.
I think the 3T77A was the first of Tek's attempts. I clearly remember that
one of the 3 Series sampling sweeps was labeled that way.
-John
================
David wrote:
There are many ways to get a waveform using sampling. All of those
that sample waveforms that are higher bandwidth than the sampling rate
are storing only small parts of many, many, repetitions of the signal
under test. In the case of the 7D20, and the 7854, you may be looking
at snippets of hundreds of repetitions of that signal, just to get a
look
at a single copy. In the days of old, these were called sampling
oscilloscopes. My old Tektronix catalogs always refer to them as digitizers or
digital storage oscilloscopes. The term sampling was always
associated with instruments that had actual sampling front ends. It doesn't matter what they call it, if it can't store the whole
waveform in one shot, it is a sampling scope, just as sure as the
old N, 1SXX, 7SXX, etc. plugins were. The prime difference is the
old type N, 1SXX, and 7Sxx plugins used the screen's phosphor, in
combination with the refresh rate, to "store" the sampled bits long
enough for you to see the full waveform. The 7D20, and 7854 use
digital storage bins, filled in a fairly chaotic way, to store the
sampled bits for view. If you have ever watched a 7854 store a
400MHz sine wave using its 50K sampling rate, you know what I mean.
If you have it set to display the stored bits as they come in, you
will see dots randomly appear on the screen (like snowflakes) as
the waveform is generated in the digital memory.
I never picked up a 7D20 because it lacks peak detection but the slow
waveform regeneration rate of my 2230 has only rarely been a problem. I use a 7854, or a 7D20, quite a lot... but only in the single shot
mode. I usually only need storage to handle things that are slower
than my visual refresh rate.
-Chuck Harris
|
Re: Oscilloscopes - analog but with digital capability?
David,
Thanks for the clarification -- that makes more sense than what I "remembered". And 2230 sounds right.
Happy New Year!
Erich
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--- In hp_agilent_equipment@..., David <davidwhess@...> wrote:
It was almost certainly a 2230 (100 MHz and 20 MS/sec) or 2220 (60 MHz
and 20 MS/sec) which came out in 1986 or at least first showed up in
that year's catalog.
The sample clock is not dithered but instead the difference between
the trigger and sample clock is measured to within about 500ps which
allows the acquired samples to be positioned within the waveform
record. In order to gain anything from that process, the signal being
measured and the sample clock have to be asynchronous.
It is my most used oscilloscope although the updated version in the
form of the 2232 is superior in almost every way.
On Mon, 31 Dec 2012 17:40:05 -0000, "erich_schlecht"
<schlechtca@...> wrote:
Speaking of old scopes, the first digital scope I got circa 1986 was a Tek with a sample rate around 20 or 50 Msps, bandwidth 100 or 200 MHz. For repetitive signals it dithered the sample clock to reconstruct signals well above the Nyquist frequency over many cycles. It couldn't see fast single event signals, of course.
It also had a pure analog mode. For the time, it was a pretty decent instrument.Unfortunately, I've long forgotten the model number, but it looked like a 24xx series.
Erich
--- In hp_agilent_equipment@..., Chuck Harris <cfharris@> wrote:
Hi Peter,
As I said, "any competently designed DSO". An analog scope gives
you the full vertical bandwidth regardless of the timebase setting.
A competently designed DSO should also.
You can be a bit flexible about that requirement, though. If the
aliasing effects are too fast to see at a particular timebase
setting, it would be ok to slow the sample rate until they are
only marginally too fast to see.
-Chuck Harris
Peter Gottlieb wrote:
But it's not just filtering above the Nyquist. There are other ways a sampling
digital scope can give you a wrong picture of reality. If all of these scopes
ran their digitizers constantly at full rate, watched for envelope effects and
so forth they would go a long way towards eliminating these unwanted erroneous
displays.
Peter
On 12/31/2012 10:56 AM, Chuck Harris wrote:
If by "trust" you mean see things faster than the Nyquist
limit, I fully agree.
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Re: Oscilloscopes - analog but with digital capability?
Ed,
That's probably right: 2230 sounds right. I had been thinking it was the 2430, but I think Victor is right, the 2430 doesn't have analog mod.
We picked it over HP (harder to use, jaggy display) and Gould (faster, but enormous and hard to use). Never regretted it.
Erich
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--- In hp_agilent_equipment@..., "Ed Breya" <edbreya@...> wrote:
We introduced the 2230 world-wide in the fall of 1985, so 1986 was the big year for it. It has equivalent-time sampling for display of repetitive signals up to 100 MHz, and peak detection for anti-aliasing envelope display of undersampled signals, and it operates in regular analog scope mode - equivalent to the 2235, which it was based on. The 2220 was the same, but lesser BW to fill the lower market spot. The 2232 followed, with many improvements - especially 100 Ms/sec sampling rate.
Ed
--- In hp_agilent_equipment@..., David <davidwhess@> wrote:
It was almost certainly a 2230 (100 MHz and 20 MS/sec) or 2220 (60 MHz
and 20 MS/sec) which came out in 1986 or at least first showed up in
that year's catalog.
The sample clock is not dithered but instead the difference between
the trigger and sample clock is measured to within about 500ps which
allows the acquired samples to be positioned within the waveform
record. In order to gain anything from that process, the signal being
measured and the sample clock have to be asynchronous.
It is my most used oscilloscope although the updated version in the
form of the 2232 is superior in almost every way.
On Mon, 31 Dec 2012 17:40:05 -0000, "erich_schlecht"
<schlechtca@> wrote:
Speaking of old scopes, the first digital scope I got circa 1986 was a Tek with a sample rate around 20 or 50 Msps, bandwidth 100 or 200 MHz. For repetitive signals it dithered the sample clock to reconstruct signals well above the Nyquist frequency over many cycles. It couldn't see fast single event signals, of course.
It also had a pure analog mode. For the time, it was a pretty decent instrument.Unfortunately, I've long forgotten the model number, but it looked like a 24xx series.
Erich
--- In hp_agilent_equipment@..., Chuck Harris <cfharris@> wrote:
Hi Peter,
As I said, "any competently designed DSO". An analog scope gives
you the full vertical bandwidth regardless of the timebase setting.
A competently designed DSO should also.
You can be a bit flexible about that requirement, though. If the
aliasing effects are too fast to see at a particular timebase
setting, it would be ok to slow the sample rate until they are
only marginally too fast to see.
-Chuck Harris
Peter Gottlieb wrote:
But it's not just filtering above the Nyquist. There are other ways a sampling
digital scope can give you a wrong picture of reality. If all of these scopes
ran their digitizers constantly at full rate, watched for envelope effects and
so forth they would go a long way towards eliminating these unwanted erroneous
displays.
Peter
On 12/31/2012 10:56 AM, Chuck Harris wrote:
If by "trust" you mean see things faster than the Nyquist
limit, I fully agree.
|
Re: Oscilloscopes - analog but with digital capability?
Hi,
the 3T77(A) uses two ramps to sample, the slow one gives the screen
position, and the fast one gives the time increment AFTER the trigger event.
Random sampling uses a constant internal sampling clock, and the trigger
event is used in a fast ramp to measure the time interval between sample
and trigger event, thus determining the screen write position.
IMHO is doesn't have the feature of random sampling, the 7S11/7T11 has
ist, selectable by a pushbutton.
Regards, Jochen DH6FAZ
Am 01.01.2013 19:34, schrieb J. Forster:
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Chuck,
The random sampling is intentional and is done to reduce the artifacts of
precisely spaced samples.
I think the 3T77A was the first of Tek's attempts. I clearly remember that
one of the 3 Series sampling sweeps was labeled that way.
-John
================
David wrote:
There are many ways to get a waveform using sampling. All of those
that sample waveforms that are higher bandwidth than the sampling rate
are storing only small parts of many, many, repetitions of the signal
under test. In the case of the 7D20, and the 7854, you may be looking
at snippets of hundreds of repetitions of that signal, just to get a
look
at a single copy. In the days of old, these were called sampling
oscilloscopes. My old Tektronix catalogs always refer to them as digitizers or
digital storage oscilloscopes. The term sampling was always
associated with instruments that had actual sampling front ends. It doesn't matter what they call it, if it can't store the whole
waveform in one shot, it is a sampling scope, just as sure as the
old N, 1SXX, 7SXX, etc. plugins were. The prime difference is the
old type N, 1SXX, and 7Sxx plugins used the screen's phosphor, in
combination with the refresh rate, to "store" the sampled bits long
enough for you to see the full waveform. The 7D20, and 7854 use
digital storage bins, filled in a fairly chaotic way, to store the
sampled bits for view. If you have ever watched a 7854 store a
400MHz sine wave using its 50K sampling rate, you know what I mean.
If you have it set to display the stored bits as they come in, you
will see dots randomly appear on the screen (like snowflakes) as
the waveform is generated in the digital memory.
I never picked up a 7D20 because it lacks peak detection but the slow
waveform regeneration rate of my 2230 has only rarely been a problem. I use a 7854, or a 7D20, quite a lot... but only in the single shot
mode. I usually only need storage to handle things that are slower
than my visual refresh rate.
-Chuck Harris
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Hi all,
I wish you have a nice 2013!
Well, I am working on an 8657A which has no output. So far, following Service Manual (SM) troubleshooting guidance, I have found that there is signal output from the A6 assembly. So it goes to the attenuator assembly and vanishes.
I have a simple question: do the attenuaotrs on this unit generate any mechanical noise or are they some kind of electronic switches?
I am following the tests on the SM (SS7) and there is so far a difference on a control signal, but it would mean just a wrong attenuation setting, but not a fully missing signal.
Any hint will be welcomed!. It is my very first 8657A :-)
Regards,
JOSE
--
73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN)
AGVradio
Personal WEB
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Re: Oscilloscopes - analog but with digital capability?
This is one of the best demos of the use of a scope (a Tek 2232, btw) to use all the functions of the scope to examine different waveforms:
<>
Very very good. The internet at its best...
Dave
-=-=-=-
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On 1 January 2013, at 3:51 AM, f1gwr wrote: Yeah !
IMHO this instrument was THE great successor of the legendary 465: easy to use (except menus) and exceptional & reliable readings due to the top performance "peak-det" feature implemented in this very instrument. I used most the digital mode because it was so trustable! After many years I sold it for more recent models. And finally missed it and bought a used 2232 which featured many nice improvements over the former. This one is now my prefered general purpose workhorse among three others (2440, 2467BHD & HP 54542A). A friend of mine which I adviced to buy a 2232 said that this was really what he long awaited for...
Congrats for the great job! I suspect later scopes were not designed by the same team... Right ?
Christian F1GWR
Le 1 janv. 2013 à 04:39, "Ed Breya" <edbreya@...> a écrit :
We introduced the 2230 world-wide in the fall of 1985, so 1986 was the big year for it. It has equivalent-time sampling for display of repetitive signals up to 100 MHz, and peak detection for anti-aliasing envelope display of undersampled signals, and it operates in regular analog scope mode - equivalent to the 2235, which it was based on. The 2220 was the same, but lesser BW to fill the lower market spot. The 2232 followed, with many improvements - especially 100 Ms/sec sampling rate.
Ed
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Re: HP 8970B firmware v2800+ wanted
Christian,
Just sent you the 8970B, Opt H18 firmware files by PM.
Joe
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-----Original Message----- From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...] On Behalf Of f1gwr Sent: Sunday, December 30, 2012 3:54 PM To: hp_agilent_equipment@... Subject: [hp_agilent_equipment] HP 8970B firmware v2800+ wanted
In order to use a HP 8757A SNA as a display, the noise figure meter 8970B
requests version 2800 at least to enable special functions 47.x as described in Product Note 8970B/S-4. My datecode is only 2725 yelding E36 error. Bad luck!
To display firmware release enter 99.9 SP on the 8970B.
If someone could provide me with related ROM dump, would be great!
Almost two years ago I posted the above message, but till now did not get suitable answer. Maybe someone could read a recent ROM and post it? Please note K04BB's site only holds 2705 version of the firmware ROM, see: )_ROM_Images_and_Drivers/HP_8970B So I'm looking for 2800 release or later. Thanks for your help, Christian
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David Hess