fluke 6080A signal generator
Hello,
This is not the group to post but a quesrtion : I've got a fluke 6080A signal generator [ -140dbm-?+20dBm, 10khz..1056 MHz] which doesn't produce any outpurt and had problems with its attenuator which is switched with small rf teledyne relais. Anyone expierience in this group with repairing this kind of very solid build generator with this symtoms?
any help would be apreciated
regards jac pe1kxh?
|
Re: N-Connectors at uW Frequencies
I ran into this question some time back, and found the following:
The posting has seemed to move around within the keysight web pages from time to time, but a search for "A Signal Analyzer Connector Puzzler" should get to the document.
It appears the trade-off is related to mechanical robustness of N connectors.
|
Hello group! Anyone ever work on these? I have one that I am working on but having issues. #1, it says it's model 8709A on the front, but the manual for the 8709B appears closer. That is not helping. Initially it did not work at all... power rails off. I replaced a shorted zener and an open (!) transistor in the -20V supply and that got it working... sort of. This unit has an "inverting output amp" (from the "B" manual - not in the "A" manual) but when that is attached, the power rails are bad again. (it has one op-amp on it, so it's most likely bad. But worrying about that later. Disconnected for now) It's quite difficult to adjust the power rails for proper +/- 20V. Somewhat interactive (?) and they vary depending on the state of the instrument. (for example if I have an RF signal at the input or not) From 20V w/RF down to about 16V w/o it. This fluctuation also affects the 20.278 MHz oscillator frequency. (w/o RF input it measures about 17 MHz and unstable) So, if I input 20.278 MHz and adjust the oscillator for 20.278 MHz, the "unlock" light flashes at about a 0.5 Hz rate, and the output error voltage is swinging up/down along with it. Basically I cannot get it to lock. I suspect the power supply is still not quite right OR something is tugging on it such that it goes into current limit. The +20V rail is the worst. I might try an external supply but not easily done with this old beast. I should also as a matter of course check/replace electrolytics... Thoughts and suggestions welcome! Mark 
|
I have an 8648C that I bought second hand, great Sig Gen. Yesterday I got in
a new Siglent SSA3021X Spectrum Analyzer.
I decided to run some tests on both. If I set the 8648c to -20dBm, I see -20.57
dBm on the Siglent, not that much to worry about.
If I reduce the level on the 8648C to -80dBm, the value on the Siglent is around
-80 dBm, but it fluctuates +/- a Db or so. Now, -80dBm = 22.4uV at 50 ohms.
If I set the 8648C to 22.4 uVemf, the Siglent reads around 10 uV ?? Switching the
Siglent to read dBm, I get around -87 dBm.
The Siglent seems consistent, but the 8648C seems to have an issue switching
between dBm and uVemf.
I expect this is a cockpit error, so I am here to ask for some clarity.
Thanks for your assistance,
73, Dick, W1KSZ
|
Re: Are there any HP CRT refrenece documents?
Hi Toby
Thank you for the CRT Part number you posted
I have updated the CRT list with missing information that you have provided
the file is in the Clipboard
Best Regards Paul
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected][mailto: [email protected]] On Behalf Of Toby Sent: 28 April 2020 15:05 To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] Are there any HP CRT refrenece documents? On 2020-04-27 2:50 PM, Jeremy Nichols wrote: Here is a list I have compiled. It is nowhere near complete; I hope it
is correct.
I've found that the installed part number can be different from the one specified in the service manual parts list or as options. Having "source" listed in such a list could be interesting. (e.g. "seen installed", "service manual", "not listed but tested ok", or option number). --Toby Jeremy
HP CRTs
G-205E-2 ?175A Oscilloscope (P31)
The following all carry the first four digits "5083-"
0353 130C Oscilloscope
0722 132A Oscilloscope (dual gun)
0652 140A Oscilloscope
9093 140T Oscilloscope
1452 141A Storage Oscilloscope
2587 141T Storage Oscilloscope
2511 141T Storage Oscilloscope
1752 143A Oscilloscope (P31)
1722 143A Oscilloscope (P2)
1751 143A Oscilloscope (P?)
1732 143A Oscilloscope (P7)
1442 143A Oscilloscope (P11)
0842 H30-175A Oscilloscope, high writing-rate CRT
3552 1740A Oscilloscope
5070 1741A Storage Oscilloscope
9023 180E Oscilloscope
1952 181T Storage Oscilloscope
5791 8510 Network Analyzer
3975 Unknown, seen for sale on eBay
1875 Unknown, eBay rectangular
6589 Unknown, eBay rectangular
5732 Unknown, eBay rectangular
6577 Unknown, eBay rectangular
5751 Unknown, eBay rectangular
5723 Unknown, eBay rectangular
On Mon, Apr 27, 2020 at 11:08 AM walter shawlee <walter2@...
<mailto:walter2@...>> wrote:
With Tektronix, there is both a detailed CRT data dump, and a "used
in" index for CRTs, but I have never found anything similar for HP.?
does anyone know of any hp CRT reference data out there?? any info
appreciated, as I have failed to find any for 30+ years. It seems
like it must exist but I just don't know how to fin dit.
best regards,
walter (walter2 -at- sphere.bc.ca <>)
sphere research corp.
----- No virus found in this message. Checked by AVG - www.avg.com Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18 Internal Virus Database is out of date.
|
Re: N-Connectors at uW Frequencies
Take a look on E-bay for HP precision N to SMA bulkheAD CONNECTORS. i'VE BOUGHT THEM FOR AS LITTLE AS $10.00. Someone recently commented that the SWR input to the counter was about 4:1 - at that point, the connector may not be the dominant effect. Cheers! Quoting Paul Bicknell <paul@...>:
Hi
From memory the Ebay price is the same as I was quoted as new several years
ago
I was thinking of them as an alternative to a replacement for broken APC
3.5 on the front of HP test equipment
Best Regards Paul
_____
From: [email protected]
[mailto:[email protected]] On Behalf Of DF6NA Rainer
Sent: 28 April 2020 21:24
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] N-Connectors at uW Frequencies
Hi Paul,
the prices are shocking !
dapters-pair-TWO-PIECES/223960329767?hash=item3425136e27:g:Qj8AAOSweJxdkyDg
I have seen some used in high quality test equipment and I believe them to
be very good.
73, Rainer
Am 28.04.2020 um 21:47 schrieb Paul Bicknell:
Hi Rainer
In the past I have looked at Aeroflex Planar Crown but cannot remember how
good they are compared to a APC 3.5 or a 2.92 connector
Do you have any practical experience in using them also approximate cost
of bulkhead and adapters each side to APC 3.5
Regards Paul
_____
From: <mailto:[email protected]>
[email protected]
[mailto:[email protected]] On Behalf Of DF6NA Rainer
Sent: 28 April 2020 17:15
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] N-Connectors at uW Frequencies
Hi Gedas,
N connectors will work above 20GHz but are not reliable. I use my 8563A with
N connector also up to 26.5GHz.
But I recently changed the N connector on my 5350B to Aeroflex Planar Crown.
So I can have N / SMA / APC3.5 or even APC2.92
on the input. HP has N connectors on the 5350B, APC3.5 on 5351B and APC2.4
on 5352B.
73, Rainer
Am 28.04.2020 um 16:54 schrieb Gedas:
I am evaluating an Agilent E4408B SA for a friend which goes to 26.5 GHz.
The RF input connector is a female N-connector.
Are there some N-connectors that will operate that high or is the connector
Agilent using on this TE (and others) a compromise above 18GHz-20 GHz?
Gedas, W8BYA EN70JT
Gallery at
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 4/28/2020 2:52 AM, DF6NA Rainer wrote:
Hi,
that's what you are looking for. The N connector is good to 20GHz. The
APC3.5 is needed for up to 26.5GHz.
73, Rainer
Am 28.04.2020 um 02:00 schrieb John Gord via groups.io:
Jim,
Could you provide a close-up photo of the damaged connector?
--John Gord
On Mon, Apr 27, 2020 at 09:50 AM, Jim Potter wrote:
The high-frequency input connector on an HP 5351B I just purchased appears
to be missing the input connector. I believe it was an APC-3.5. There
appears to be a missing insert. I'm looking for tips on how to repair or
replace this connector. For my purpose a type N connector would be
acceptable as a replacement. I have the service manual. It looks like there
is a cable assembly. One part number for the APC-3.5 and one for the type N.
Thanks, Jim
No virus found in this message.
Checked by AVG - www.avg.com <>
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.
|
Velocity of propagation (so I can determine insertion delay) for a 3.5mm coax adapter?
I'm trying to work out relationship of insertion delay (as measured with VNA in picoseconds) and insertion length (as might be specified for a device, in millimeters). My goal is to determine the insertion delay (picoseconds) of an adapter where no specifications seem to exist.
In this case, the "device under test" is one of those female-to-female 3.5mm bulkhead panel adapters that seem to be pulls from a variety of HP microwave test equipment (they show up on ebay frequently.) There are no specs that I'm aware of for the part. The physical length is ~30.9 mm (my measurement). The insertion length (presumably based on knowing the reference plane) is not known to me at this point. The insertion delay is the unknown I'm interested in finding.
All searches on this so far have turned up nothing, and Joel Dunsmore's book doesn't seem to discuss the topic (at least I've not found the needed paragraph yet.) My goal is to be able to use the bulkhead adapter in VNA measurements (I'd prefer to have "real" characterized adapter such as HP 83059B or other) but that is not in my parts bin, and the bulkhead adapter is.
When measuring delay (on HP 8753) I get a delay in picoseconds (round-trip delay, because I'm inserting the adapter into the reflection signal path.) Te one-way delay (half of round trip) was measured as 93 pSec. If I convert insertion delay (one-way) in pSec to mm using velocity of propagation of 1 (full speed of light) I get an insertion length of 27.93 mm.This seems plausible (given the physical length of the adapter is 30.9 mm), but I think assuming velocity of propagation of 1.0 is improper, as the signal is propagating in something other than a vacuum. As the adapter is 3.5mm type, there is mostly air dielectric (save for a small internal disc).
Any advice, pointers, or suggestions as to how I can proceed, or where I can go to learn about this (which is basically why I'm doing this!)
Thanks very much,
Dave
wb0gaz@...
|
Hello,
This email message is a notification to let you know that the following files have been uploaded to the Files area of the [email protected]
group.
Uploaded By:
Paul Bicknell <paul@...>
Description:
latest CRT Parts number list
Cheers,
The Groups.io Team
|
Re: N-Connectors at uW Frequencies
Hi
?
From memory the Ebay price is the same as I
was quoted as new several years ago
?
I was thinking of them as an alternative to
a replacement for broken? APC 3.5 on the front of HP test equipment
?
Best Regards Paul
?
Hi Paul,
the prices are shocking !
I have seen some used in high quality test equipment and I believe them to be
very good.
73, Rainer
Am 28.04.2020 um 21:47 schrieb Paul Bicknell:
toggle quoted message
Show quoted text
Hi Rainer
?
In the past I have looked at Aeroflex Planar Crown but cannot remember
how good they are compared to a? APC 3.5? or a? 2.92
connector??
Do you have any practical experience in
using them? also approximate cost? of bulkhead and adapters each side
to? APC 3.5
?
Regards Paul
?
?
Hi Gedas,
N connectors will work above 20GHz but are not reliable. I use my 8563A with N
connector also up to 26.5GHz.
But I recently changed the N connector on my 5350B to Aeroflex Planar Crown. So
I can have N / SMA / APC3.5 or even APC2.92
on the input. HP has N connectors on the 5350B, APC3.5 on 5351B and APC2.4 on
5352B.
73, Rainer
Am 28.04.2020 um 16:54 schrieb Gedas:
I
am evaluating an Agilent E4408B SA for a friend which goes to 26.5 GHz. The RF
input connector is a female N-connector.
Are
there some N-connectors that will operate that high or is the connector Agilent
using on this TE (and others) a compromise above 18GHz-20 GHz?
Gedas, W8BYA EN70JT ? Gallery at Light travels faster than sound.... This is why some people appear bright until you hear them speak.
On 4/28/2020 2:52 AM, DF6NA Rainer wrote:
Hi,
that's what you are looking for. The N connector is good to 20GHz.? The
APC3.5 is needed for up to 26.5GHz.
73, Rainer
Am 28.04.2020 um 02:00 schrieb John Gord via groups.io:
Jim,
Could you provide? a close-up photo of the damaged connector?
--John Gord
On Mon, Apr 27, 2020 at 09:50 AM, Jim Potter wrote:
The high-frequency
input connector on an HP 5351B I just purchased appears to be missing the input
connector. I believe it was an APC-3.5. There appears to be a missing insert.
I'm looking for tips on how to repair or replace this connector. For my purpose
a type N connector would be acceptable as a replacement. I have the service
manual. It looks like there is a cable assembly. One part number for the
APC-3.5 and one for the type N.
Thanks, Jim
No virus found in this message.
Checked by AVG -
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.
?
|
Re: N-Connectors at uW Frequencies
Hi Paul,
the prices are shocking !
I have seen some used in high quality test equipment and I believe
them to be very good.
73, Rainer
Am 28.04.2020 um 21:47 schrieb Paul Bicknell:
toggle quoted message
Show quoted text
Hi Rainer
?
In the past I have
looked at Aeroflex Planar Crown but cannot
remember
how good they are compared to a? APC 3.5? or a? 2.92
connector??
Do
you have any practical experience in
using them? also approximate cost? of bulkhead and
adapters each side
to? APC 3.5
?
Regards
Paul
?
?
Hi Gedas,
N connectors will work above 20GHz but are not
reliable. I use my 8563A with N
connector also up to 26.5GHz.
But I recently changed the N connector on my 5350B to
Aeroflex Planar Crown. So
I can have N / SMA / APC3.5 or even APC2.92
on the input. HP has N connectors on the 5350B, APC3.5
on 5351B and APC2.4 on
5352B.
73, Rainer
Am 28.04.2020 um 16:54 schrieb Gedas:
I
am evaluating an Agilent E4408B SA for a friend which
goes to 26.5 GHz. The RF
input connector is a female N-connector.
Are
there some N-connectors that will operate that high or
is the connector Agilent
using on this TE (and others) a compromise above
18GHz-20 GHz?
Gedas, W8BYA EN70JT
?
Gallery at
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 4/28/2020 2:52 AM, DF6NA Rainer wrote:
Hi,
that's what you are looking for. The N connector
is good to 20GHz.? The
APC3.5 is needed for up to 26.5GHz.
73, Rainer
Am 28.04.2020 um 02:00 schrieb John Gord via
groups.io:
Jim,
Could you provide? a close-up photo of the damaged
connector?
--John Gord
On Mon, Apr 27, 2020 at 09:50 AM, Jim Potter
wrote:
The high-frequency input connector on an
HP 5351B I just purchased appears
to be missing the input connector. I believe it
was an APC-3.5. There appears
to be a missing insert. I'm looking for tips on
how to repair or replace this
connector. For my purpose a type N connector would
be acceptable as a
replacement. I have the service manual. It looks
like there is a cable
assembly. One part number for the APC-3.5 and one
for the type N.
Thanks, Jim
No virus
found in this message.
Checked by AVG -
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release
Date: 08/14/18
Internal Virus Database is out of date.
|
Re: Question regarding HP 334A (Distortion Analyzer)
I checked the indicated transistors and they check good.
HOWEVER:
I noticed that if I change the frequency range switch to a different range, A5TP4 springs to life. Basically, if the input frequency is anywhere near the the frequency set on the distortion analyzer, then there's virtually nothing at A5TP4.
Is this normal? The troubleshooting section for Schematic 4 shows the settings for the various controls and to what value the incoming frequency should be set but when I do that, A5TP1 has an active square wave but A5TP4 is virtually at ground potential.
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "Barry" <n4buq@...>
To: [email protected]
Cc: [email protected]
Sent: Monday, April 27, 2020 10:36:57 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Question regarding HP 334A (Distortion Analyzer)
I just now noticed that in the troubleshooting section (Table 5-8, "3.
AUTOMATIC MODE INOPERATIVE") it describes exactly what I'm seeing:
SYMPTOM
B. No indication of square wave at A5TP4. A5TP1 normal square wave
indication.
PROBABLE CAUSE
Check A5Q15 through A5Q18 and A5Q12.
I think I've checked those (at least using my DMM's diode check mode) but
will do so again. Maybe I missed something there.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "n4buq" <n4buq@...>
To: [email protected]
Sent: Monday, April 27, 2020 10:18:12 PM
Subject: [HP-Agilent-Keysight-equipment] Question regarding HP 334A
(Distortion Analyzer)
As I've mentioned, I've been doing some troubleshooting for the AUTO
circuitry in my 334A as it is not working properly. I've examined the
voltages on the schematic as well as the waveforms and, while they're not
exactly like the values and images in the document, they do exhibit a
relative resemblance - at least for the RESISTIVE CONTROL LOOP. The
waveforms for the REACTIVE CONTROL LOOP, however, are not at all correct.
I'm seeing mostly nothing at all for those.
While I can't say I completely understand the signal flow, I do see
something
that I do not understand and am pretty sure is incorrect (and possibly the
root cause of the REACTIVE CONTROL LOOP failure).
If I look at the signal at A5Q7's emitter, I see a clean sine wave with a
small negative offset (enough that the entire waveform is negative). I
don't remember the exact values but I think it's about a 1V p-p riding at
about 2V negative. That emitter is tied to one side of A5R57 and the other
side of A5R57 is tied to the negative end of A5C24. I see the waveform at
the side of that resistor that's tied to A5Q7, but the other side of that
resister shows nothing - pretty much as if it is at ground pontential.
I assume that same signal (with, perhaps, some attenuation) should be seen
at
the base of A5Q15 but it isn't. Is it correct that the waveform should be
seen there? If so, what could possibly be causing it to be lost? I
suspect
an open A5C24 but I haven't proven that. I may lift one side and check it
that way but with it in-circuit, my universal component checker thingee
doesn't recognize it as a valid part (e.g. states it is "missing" or
"broken", etc.).
Essentially, A5TP1 is a square wave that toggles the detector A5Q4 and I do
see that; however, I see nothing like that at A5TP4 so I suspect there's a
problem somewhere in the PHASE LAG or REFERENCE AMPLIFIER circuits.
Anyone familiar with these circuits and maybe give me some pointers?
Thanks,
Barry - N4BUQ
|
Re: N-Connectors at uW Frequencies
Hi Rainer
?
In the past I have looked at Aeroflex Planar Crown but cannot remember
how good they are compared to a? APC 3.5? or a? 2.92 connector??
Do you have any practical experience in
using them? also approximate cost? of bulkhead and adapters each side
to? APC 3.5
?
Regards Paul
?
?
Hi Gedas,
N connectors will work above 20GHz but are not reliable. I use my 8563A with N
connector also up to 26.5GHz.
But I recently changed the N connector on my 5350B to Aeroflex Planar Crown. So
I can have N / SMA / APC3.5 or even APC2.92
on the input. HP has N connectors on the 5350B, APC3.5 on 5351B and APC2.4 on
5352B.
73, Rainer
Am 28.04.2020 um 16:54 schrieb Gedas:
I
am evaluating an Agilent E4408B SA for a friend which goes to 26.5 GHz. The RF
input connector is a female N-connector.
Are
there some N-connectors that will operate that high or is the connector Agilent
using on this TE (and others) a compromise above 18GHz-20 GHz?
Gedas, W8BYA EN70JT ? Gallery at Light travels faster than sound.... This is why some people appear bright until you hear them speak.
On 4/28/2020 2:52 AM, DF6NA Rainer wrote:
Hi,
that's what you are looking for. The N connector is good to 20GHz.? The
APC3.5 is needed for up to 26.5GHz.
73, Rainer
Am 28.04.2020 um 02:00 schrieb John Gord via groups.io:
Jim,
Could you provide? a close-up photo of the damaged connector?
--John Gord
On Mon, Apr 27, 2020 at 09:50 AM, Jim Potter wrote:
The high-frequency input connector on an HP 5351B I just purchased appears
to be missing the input connector. I believe it was an APC-3.5. There appears
to be a missing insert. I'm looking for tips on how to repair or replace this
connector. For my purpose a type N connector would be acceptable as a
replacement. I have the service manual. It looks like there is a cable
assembly. One part number for the APC-3.5 and one for the type N.
Thanks, Jim
No virus found in this message.
Checked by AVG -
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.
|
Re: N-Connectors at uW Frequencies
Yup fully understand all
this......even going to 22 GHz can be risky depending on what
you are doing but using a N-connector at 26.5 GHz still
puzzles me esp for later models made by Agilent. Not sure if
any KS models use them. 26.5 GHz is starting to get up there
<g>.
Gedas, W8BYA EN70JT
Gallery at
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 4/28/2020 3:02 PM, Stuart Landau via
groups.io wrote:
toggle quoted message
Show quoted text
You might note that many of the Hewlett Packard spectrum analyzers
of the past, that went much higher than 18 GHz, use female type N
connectors on their inputs; this includes the popular 8566A and B.
That doesn't make it right, but I guess they used what was
available at the time.
The earlier lab type N connectors were not used above about 12
GHz. They were upgraded to 18 GHz for precision connectors and
adapters.?
Using the wrong series type N connector isn't going to do damage,
but your measurements may not be accurate.
|
Re: HP 4195A NiCad Battery replacement
Tobias,
In the 4194A you can store 3 OSL cal data with frequency range, etc...
That's an nice feature since it's ready, right from power on, with up to the 3 cal/config you need for the current job.
Maybe HP felt this was less needed for typical VNA use.
Another reason may be that, AFAIK, the 4194A was designed byt HP/Yokogawa and the 4195A was in the US, but on the same HW plateform.
Two design teams hence two different machines. One thing in favor of this is that the 4195A and 4194A do not share much in matter of user interface.
I don't think there's any good reason to prevent it to start from low battery (except maybe marketing teams looking for opportunity to brick it).
But from experience don't underestimate design teams abitility to get something wrong from time to time, even at this level and also even from HP, Tek, and some other good ones.
I do have a very nice lab with lots of instruments accumulated over years, so had to reverse/fix quite a bunch of, and found my share of strangeness.
Hey they're humans, ain't they?
The last one is a fixed 4291A that did not start. The PSU was, I believe, a co-design from HP and Murata.
Apart from 2 toasted BJTs and a pair of dried Al caps (0.47uF for PSU startup timing) they also included fan rotation monitoring as a startup condition.
That's nice, but after I "painfully" closed the machine (lots of screws,...) it soon decided to brick again.
The fan grease (not the Grease fan...) had thickened a bit with time and sure enough, the startup window allowing the fan to speedup was dangerously too close to the limit (no need for half a second timeout. 2 or 5 or even 10 seconds would have been perfect).
No good reason for that, except it worked at design time and this was good enough...
Thanks,
Fred
|
Re: HP 4195A NiCad Battery replacement
Almost all the NiCd?battery charging circuits in intruments (and this one is no exception) are trickle charging the battery because this is simple and NiCd chemistry withstand this well.
NiMh cells do not shine there and you're over and over and over charging it, while the instrument is on and until it's soon toasted.
Thanks,
Fred
I am not an expert, but from what I have read, if you reduce reduce the charge current NiMH will be fine to replace NiCd. From memory C/20 is fine. You can achieve that by just using high capacity NiMH cells in place of the older lower capacity NiCd cells.
I have some ?emergency lights. When the D-cells NiCd failed, I replaced with high capacity (10 Ah) NiMH D-cells. I ?don¡¯t know what they are charged at, ?but they have been trickle charged for years, and a few months ago kept working during a 13-hour power?outage. The lights were speced to last 4 hours, but worked much longer as I used high capacity cells.??
I think the original spec on the lights was they took 24 hours to recharge, which would suggest a charge rate of about C/20. With NiMH that is probably C/60.?
Be aware, there are a lot of fake NiMH cells with capacities much smaller than claimed.?
Dave.? -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@...Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
|
It's working! Interesting problem, never would have found it without the CLIPs. There are a number of voltage 'sub-regulators' and filters downstream of the main power supply. One filter, an inductor between +12V coming into the main A1 board and a +10v sub-regulator and some other analog circuitry was open. Not a bad solder joint, inductor itself was open. Replaced? it with a very low inductance one I had on hand (a strand of wire), passes all checks, interpolators now calibrate.
Even more interesting is how well it worked without power to the entire gain/offset circuitry for both interpolators.
Bill
|
Re: N-Connectors at uW Frequencies
You might note that many of the Hewlett Packard spectrum analyzers of the past, that went much higher than 18 GHz, use female type N connectors on their inputs; this includes the popular 8566A and B. That doesn't make it right, but I guess they used what was available at the time.
The earlier lab type N connectors were not used above about 12 GHz. They were upgraded to 18 GHz for precision connectors and adapters.?
Using the wrong series type N connector isn't going to do damage, but your measurements may not be accurate.
|
Re: HP 4195A NiCad Battery replacement
Correct - The reset circuit checks the battery voltage under charge. It measures the battery voltage and the charging current and
suppresses the Reset signal for both CPUs.
Cheers!
Bruce
Quoting Fr¨¦d¨¦ric BARTOLI <fred.bartoli@...>:
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Hi Tobias,
I didn't check what's stored in the 4195A SRAM, but for the 4194A,
some user calibration data (as when you cal a VNA with a cal kit)
and also some setup configurations (you can store of them).
The reason it don't start with an empty battery is, as I said, that
they "carefully" designed it to not start with an empty battery.
I do not remeber all the details (was more than 10 years ago) but,
from recollection, the reset circuit depends on the battery voltage
and IIRC battery charging also depends on battery voltage.
Hence a drained battery prevents it to be charged and no battery
voltage keeps the CPU in reset.
Just a nice blunder...
Fred
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Re: HP 4195A NiCad Battery replacement
Hello, User programs.
With best regards Tam HANNA (emailing on a BlackBerry PRIV) Enjoy electronics? Join 14k other followers by visiting the Crazy Electronics Lab at Am 28. April 2020 20:29:27 MESZ schrieb Tobias Pluess <tobias.pluess@...>:
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Interesting.
What types of settings are stored in that SRAM? so far I did not manage to store calibration (open short load). It is always lost when the instrument is switched off. Just checked it:
calibrate in the NETWORK mode, then switch off and on again, and calibration is lost. It does not even keep the frequency settings, number of points or RBW. So it would be really interesting, what the battery is for. Obviously it must be something "important", that HP prevented the machine from booting when the battery was dead. But what?
it is not the calibration data, as that is stored in the EEPROM.
(By the way, has someone ever managed to find replacement parts? I am very nervous about the EEPROM to go nuts. It is almost unobtanium nowadays.)
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New (off) Topic: Setting clock references on various equipment using WWV, guitar tuner, HF receiver, RF generator
I didn't mean to hijack the thread "How to check the accuracy of an HP 5342A frequency counter". So I am starting a new thread. I will paste in what I placed in the other thread too.
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I've used beat frequency method WWV with my HP counter and RF generator to set the internal references in each. Once I have used the signal strength meter on my Radio Shack HF receiver DX-160 tuned to WWV to move imperceptibly in no-fade conditions, I will use a guitar tuner also and offset my RF generator from WWV? highest broadcast frequency (20MHZ if possible) and offset by +- 440HZ (20,000,440 HZ . That is the "A" note setting on the guitar tuner, you can use a lower octave for more accuracy, (220 hz offset), but your receiver may filter that audio freq out and you won't know why you can't hear the 'beat whistle', and/or your guitar tuner may filter more than mine does, and not allow you to see the first octave (x2).? Then have the tuner mic near the SW radio speaker, Adjust the RF level out on the RF generator so it mixes with WWV and not overpower it, and you center steady up the guitar tuner needle by adjusting the source, or whatever needs adjusting. Stay away from 5MHZ WWV, noisy and better accuracy during daytime up higher freqs. At least 15 MHZ. I've done it at 25 MHZ also when it was broadcast too.
Greg Muir chimed in;
Even calibration via WWV can be a real chore if you are located some distance from the transmitters and can only receive the sky wave instead of the ground wave signal.??The erratic movement of the received signal phase gets to a point where it becomes nearly impossible to determine where you are with the DUT setting unless you can do some time variant analysis.
It's nice to have GPS handy.
Greg
My response;
To address what Greg Muir stated, that's why I use the guitar tuner. I can 'hear' when the WWV signal fades away because the beat frequency of 440 hz goes away and the tuner needle will leave center, assuming you had the reference set correctly.
Actually, I would like someone who has a better reference source and a guitar tuner, HF receiver with strength meter, RF generator, and see how accurate my method is by comparison.
NielsenTelecom
Ok, Any takers? The best response from the guitar tuner is during the quiet time when the 'tic-toc' is the only WWV audio. It will just cause the tuner needle to jump. Also, I have been able to get the beat whistle using this method even when WWV was imperceptible to the ear. The guitar tuner does a great job of filtering only what it wants.
NielsenTelecom
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Paul Bicknell
Dr. David Kirkby, Kirkby Microwave Ltd
