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Re: HP 8753B CPU issue

Bob Macklin
 

?
Bipolar/Fuseable Link PALs have the same Bit Rot problem of ROMs of that period.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
Sent: Wednesday, February 17, 2016 8:31 AM
Subject: Re: [hp_agilent_equipment] HP 8753B CPU issue

?

I'm sure you already considered, but the PAL was burned fresh, or swapped from a board of the same revision? ?As a programmable device, it is possible that the code in the PAL did change between board or prom revisions.

Note that I have no knowledge of that unit specifically but I just got burned by different PAL code on a different repair.

Nathan
KK4REY


On Wed, Feb 17, 2016 at 19:09, ChuckA chuck@... [hp_agilent_equipment] wrote:
?

I've been working on this problem 8753B CPU card for a few months now
with very limited results. The original problem was no video, which I
tracked down to a bad PAL 16R1 chip, replacing that got me a screen with
random lines and various flashing characters. I thought that problem was
bad DRAM so I replaced them, still no change. Watching the status lights
while changing the position of the A9CC jumper and pressing the "PRESET"
button I was able to get it to occasionally start to work, but not all
the time.

The short story is I can now get it to run every time by following
this procedure; turn the unit on with the A9CC jumper in the "NORMAL"
position, then move the jumper to the center position and press
"PRESET", then move the jumper to the next position to the right and
press "PRESET". This will display "DRAM Passed" on the screen, then move
the jumper back to the "NORMAL" position and press "PRESET", at which
time the unit will start up and operate normally as long as power is
applied.

Any change in that sequence and it will not operate. I've swapped the
PROM's into a working board and they work fine.

Anyone have any idea what is going on with this?

Chuck

--
See Early TV at:

www.myvintagetv.com
Re: Test Equipment where battery failure causes SERIOUS problems

Tom Miller
 

¿ªÔÆÌåÓý

No battery in the 3456A. Calibration is by knob twiddling.
?
?

----- Original Message -----
Sent: Wednesday, February 17, 2016 12:46 PM
Subject: RE: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

Does anyone know about the HP 3456A DMM? I can¡¯t remember if it requires a battery for cal memory or not.

Thanks

Gary? K4FMX

From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
Sent: Wednesday, February 17, 2016 8:10 AM
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

The 859X series spectrum analyzers loose: band leveling offsets, attenuator corrections, and clock corrections if the memory battery dies. There is at least a procedure to copy these down from the operator interface so they can be reloaded in event of failure.?

-Kelly

On Wednesday, February 17, 2016 2:02 AM, "Peter Hansen oz1lpr@... [hp_agilent_equipment]" <hp_agilent_equipment@...> wrote:

?

Hello David?I think the HP 8756 Scalar analyzer?Looses all the Channel calibration data if the battery is lost. This requires?programming through a HP computer with obsolete software.
best regards Peter Hansen
?

To: hp_agilent_equipment@...
From: hp_agilent_equipment@...
Date: Tue, 16 Feb 2016 21:39:40 +0000
Subject: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

On 16 February 2016 at 21:27, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby@...> wrote:

2) HP 3457A 6.5 digit multimeter

whilst not so catastrophic, a report I read recently on one of the newsgroups from someone, said he sent a 3457A in for calibration, and the company was not happy as the failure of the battery added an hour to the calibration time. They were going to charge for this, but in the end they did not.

Just to clarify, the extra hour was not for replacing the battery - the owner had already done that. The extra hour was for the fact every range needed zeroing and setting to full scale.?

Re: HP 8753B CPU issue

 

Well that should eliminate that issue. ?Hopefully someone here has an idea more specific to that model.

Nathan
KK4REY


On Wed, Feb 17, 2016 at 20:46, ChuckA chuck@... [hp_agilent_equipment] wrote:

?

Nathan

I swapped the new PAL into a working board with no problem, and tried
firmware version 2.01 and 3.0 PROMs and both worked.

Chuck

On 2/17/2016 11:31 AM, Nathan Johnson jdownj@...
[hp_agilent_equipment] wrote:
>
>
> I'm sure you already considered, but the PAL was burned fresh, or
> swapped from a board of the same revision? As a programmable device, it
> is possible that the code in the PAL did change between board or prom
> revisions.
>
> Note that I have no knowledge of that unit specifically but I just got
> burned by different PAL code on a different repair.
>
> Nathan
> KK4REY
>
> Sent using CloudMagic Email
>
>
> On Wed, Feb 17, 2016 at 19:09, ChuckA chuck@...
> [hp_agilent_equipment] wrote:
>
> I've been working on this problem 8753B CPU card for a few months now
> with very limited results. The original problem was no video, which I
> tracked down to a bad PAL 16R1 chip, replacing that got me a screen
> with
> random lines and various flashing characters. I thought that problem
> was
> bad DRAM so I replaced them, still no change. Watching the status
> lights
> while changing the position of the A9CC jumper and pressing the
> "PRESET"
> button I was able to get it to occasionally start to work, but not all
> the time.
>
> The short story is I can now get it to run every time by following
> this procedure; turn the unit on with the A9CC jumper in the "NORMAL"
> position, then move the jumper to the center position and press
> "PRESET", then move the jumper to the next position to the right and
> press "PRESET". This will display "DRAM Passed" on the screen, then
> move
> the jumper back to the "NORMAL" position and press "PRESET", at which
> time the unit will start up and operate normally as long as power is
> applied.
>
> Any change in that sequence and it will not operate. I've swapped the
> PROM's into a working board and they work fine.
>
> Anyone have any idea what is going on with this?
>
> Chuck
>
> --
> See Early TV at:
>
> www.myvintagetv.com
>
>
>
>

--
See Early TV at:

www.myvintagetv.com
Re: HP 54542C Scope

 

On Sun, 14 Feb 2016, Orin Eman orin.eman@... [hp_agilent_equipment] wrote:

A little more on the 545xx power supplies.



So the 0950-2369 supersedes the 0950-1879 - I doubt there is much
difference given the discussion so far.
My HP54542A uses the 0950-2369 with P/N 700202-001. I did quite
some research regarding schematics without success. The supply
was from 1993 and has manufacturer part number XL130-3630E.

I would not buy any of these supplies on eBay - the likely reason the
instrument was parted out was the supply died. However, the -1879 was used
in the 1650B logic analyzer and working instruments run around $50!
That sounds a clever idea for Michael's 54542C, too! I bought one of the
chinese supplies (for much less than the current ones run) as a spare
and it works...

Best regards,

Erik.
Re: HP 8753B CPU issue

 

Nathan

I swapped the new PAL into a working board with no problem, and tried firmware version 2.01 and 3.0 PROMs and both worked.

Chuck

On 2/17/2016 11:31 AM, Nathan Johnson jdownj@... [hp_agilent_equipment] wrote:


I'm sure you already considered, but the PAL was burned fresh, or
swapped from a board of the same revision? As a programmable device, it
is possible that the code in the PAL did change between board or prom
revisions.

Note that I have no knowledge of that unit specifically but I just got
burned by different PAL code on a different repair.

Nathan
KK4REY

Sent using CloudMagic Email
<>

On Wed, Feb 17, 2016 at 19:09, ChuckA chuck@...
[hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

I've been working on this problem 8753B CPU card for a few months now
with very limited results. The original problem was no video, which I
tracked down to a bad PAL 16R1 chip, replacing that got me a screen
with
random lines and various flashing characters. I thought that problem
was
bad DRAM so I replaced them, still no change. Watching the status
lights
while changing the position of the A9CC jumper and pressing the
"PRESET"
button I was able to get it to occasionally start to work, but not all
the time.

The short story is I can now get it to run every time by following
this procedure; turn the unit on with the A9CC jumper in the "NORMAL"
position, then move the jumper to the center position and press
"PRESET", then move the jumper to the next position to the right and
press "PRESET". This will display "DRAM Passed" on the screen, then
move
the jumper back to the "NORMAL" position and press "PRESET", at which
time the unit will start up and operate normally as long as power is
applied.

Any change in that sequence and it will not operate. I've swapped the
PROM's into a working board and they work fine.

Anyone have any idea what is going on with this?

Chuck

--
See Early TV at:

www.myvintagetv.com



--
See Early TV at:

www.myvintagetv.com
Re: Test Equipment where battery failure causes SERIOUS problems

 

¿ªÔÆÌåÓý

Does anyone know about the HP 3456A DMM? I can¡¯t remember if it requires a battery for cal memory or not.

?

Thanks

Gary? K4FMX

?

From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
Sent: Wednesday, February 17, 2016 8:10 AM
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

?

The 859X series spectrum analyzers loose: band leveling offsets, attenuator corrections, and clock corrections if the memory battery dies. There is at least a procedure to copy these down from the operator interface so they can be reloaded in event of failure.?

-Kelly

?

On Wednesday, February 17, 2016 2:02 AM, "Peter Hansen oz1lpr@... [hp_agilent_equipment]" <hp_agilent_equipment@...> wrote:

?

?

Hello David?I think the HP 8756 Scalar analyzer?Looses all the Channel calibration data if the battery is lost. This requires?programming through a HP computer with obsolete software.
best regards Peter Hansen
?

To: hp_agilent_equipment@...
From: hp_agilent_equipment@...
Date: Tue, 16 Feb 2016 21:39:40 +0000
Subject: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

?

On 16 February 2016 at 21:27, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby@...> wrote:

?

?

2) HP 3457A 6.5 digit multimeter

whilst not so catastrophic, a report I read recently on one of the newsgroups from someone, said he sent a 3457A in for calibration, and the company was not happy as the failure of the battery added an hour to the calibration time. They were going to charge for this, but in the end they did not.

?

Just to clarify, the extra hour was not for replacing the battery - the owner had already done that. The extra hour was for the fact every range needed zeroing and setting to full scale.?

?

?
Re: HP 54542C Scope

 

On Sun, 14 Feb 2016, Jack Mcmullen forjack842@... [hp_agilent_equipment] wrote:

Like I said, map and draw out the over heating 350's circuit. If its being supplied by the +5.2v supply is providing a voltage reference in the 3v range. If that's 0vdc at pin 2, fix that then proceed on to isolate what hangs on the voltage bus. This ain't rocket science guys just methodical troubleshooting without a schematic.
See my thread from 2013 - I had probably a similar problem with
my 54542a which has the identical power supply:



In my case it was the -12V generation which was faulty and I already
drew the schematic in 2013...



And yes - this is no rocket science, but it is very cumbersome
to do measurements on the opened supply as the cable to the
oscilloscope is rather short ;-)

Good luck to Michael and his 54542C...

Erik.
Re: HP 54542C Scope

 

Hi Orin,

thanks for your hints to Michael and his 54542C. I had a similar Problem in 2013 with a 54542a which uses the same supply. See the thread in this
forum's archive:



than required to avoid dropout and may be dissipating excess power. The
report of 0.5V on the LM350 input sounds wrong - it's dropped out of
regulation.
Yes, that is what I observed to be the USECASE in this weired design.
In 2013 I drew out a schematic of the -12V generation, see here



The output is tied to 0V and the regulator's ground pin can
be adjusted. So the regulator actually sees a short on its
output and thus the input MUST be as low as the drop out
voltage.

The purpose of this design is (IMHO), that the switch mode supply charges the capacitor C2 to 12.5V via T and D1. Normally the input of the regulator is close to 0.5V giving an output of unregulated -12V. If there is escessive current drawn from the supply, the current flowing into the regulator increases as well and if it is above the maximum permitted value of the LM350, it is going to "open". This means the voltage at the LM350's input increases towards e.g. 3V where the -12V are changing to -9.5V (remember, C2 is still charged by the switcher to 12.5V and the switcher can supply much more current). In this way a current protection is realized...

One of the LM350s regulates the ground line of the -12V supply, so again,
voltages don't seem out of line with the adjustment pin at -1.2V.
As far as I can remember, there is another LM350 in this supply, but
this was not the problem in my case...

a little high for the 15.5V unregulated line, but without observing a
working supply, we don't know).
I had 16.12V with 200mV ripple on the 15.5V line. The ripple had the
form of small v's going to lower voltage.

I'd recommend Michael to supply the -12V from an external, current
protected supply to see, how much current the mainboard draws.
There are small switch moder regulators generating a whole bunch
of other voltages from the -12V and maybe one of the many
Tantalum Cs there is the evil part ;-)

Erik.

[hp_agilent_equipment] <hp_agilent_equipment@...> wrote:



Hi guys,
Your outpouring of help is amazing. Many comments are very relevant to
this PS, but some seem to be addressing a different version. The HP
numbers are 0950-2369, Mfg numbers XL130-3630E and the diagrams I've seen
reverse engineered are fairly accurate even though the one I saw was
created from a different version PS.

I've looked over the voltages and every rail appears to be right where it
should be. A bit noisy, but DC is very good throughout the unit. There
are some devices in the PS and on the mother board which are getting very
warm, a bit too hot to touch, but far from burning anything. One thing
I've noticed, the unit as a whole is drawing about 160 AC watts, seems a
bit high. I recall reading it should be somewhere around 145 watts? So...
I'm 'thinking' something is drawing too much current, as brought up in
thread, not enough enable shutdown but enough to create some switching
noise in the PS rails. Does that make sense?

Here what I would like to do, if this is appropriate, upload a few
seconds of capture so everyone can see what I'm seeing so I'm not confusing
anyone. I've tried several generators from 50kC to 500Mhz so I know it
isn't signal noise, I see the noise at all levels albeit much more
pronounced in the single digit milli-volt levels. One issue I personally
have is, I've this is my first 'digital' scope so I'm unfamiliar with how a
trace should appear.

~Michael - AF7U
Re: HP 3325A What ROMS?

 

Hi Joe.

Can you provide some detail on the jumper settings for the 2 rom solution??

Thanks.
Re: HP 3325A ROM Replacement

Tom Miller
 

?
Either a 27C128 or a? 1/2 of a 27C256 would do it. A small PC board with some pins to match one of the four 4k sockets as well as some chip select jumper(s) to the other socket(s). Both of these chips are supported by most programmers and the supply should persist.
?
This may be useful for many other equipment that used the same Roms.
?
I repaired a HP DMM that had Mostek Roms by installing a 24 pin socket in one position and installing the 27C128 with the four pins bent out and wired to the other sockets.
?
?
?

----- Original Message -----
Sent: Tuesday, February 16, 2016 8:00 PM
Subject: [hp_agilent_equipment] HP 3325A ROM Replacement

?


I thought I would summarize a somewhat meandering thread.

I¡¯ve received the Artek manual and it is great!?

It appears I do have a failing ROM IC.?

As time went by HP changed from 4 4k*8 chips to 2 8k*8 chips and there is a way to jumper some boards to tell it which is installed.? (Joe: is that just the A/B jumpers near U5, or is it more than that?).? Apparently there are even some 3325a¡¯s with 3 ROM ics.

The HP nano-processor only has 11 address lines for a 12 bit space and so they played games to extract the 12 bit.? In the 4-chip solution, each chip has 2 select pins which are used in such a way as to provide the top 2 most significant bits.

Thus far, I have not found a 4k*8 EPROM or EEPROM that is pin-compatible with the original Synertek Sy2332/Motorola MCM88A332 masked ROM.? The TMS2532 are almost right, but lack the second select pin. [I keep seeing this listed even in historical literature as pin-compatible, but it is not according to the data sheets.? I¡¯ve seen this so many places that I wonder if the datasheets are wrong and pin 20 can be used as a second select.]

The original 2-IC solution used the Motorola MCM68764C EEPROM.? A later version of that chip? is the Motorola MCM68766.? Joe has previously extracted the 2-IC ROM program.? I would guess that the 4-IC data is the same, just split between chips.? I also think the data is the same independent of options as otherwise the signature analysis info would have to change between machines, and it does not.

My repair options include:


4 IC¡¯s.? This looks to require some extra glue logic to decode the second select unless a pin-compatible EEPROM can be found.? It would also require me to extract my data or split the existing 2-IC data.

2 IC¡¯s.? This only requires some jumper changes and the ROM program is already available.

1 IC solution.? Because the 3325a already decodes the 2 select pins as if they¡¯re address pins, this would only require a simple pin-remapping board for the new IC.

Option B looks like the obvious choice except that I have so far only been able to find used replacement EEPROMs and I wonder about the longevity of those.

I¡¯d also like to help the next person that needs to fix the ROM in a 3325a, and that argues for Option C.? Once option C is chosen almost any parallel ROM can be used and I¡¯m seeing some flash-ROM with a listed lifetime of 100+ years.

Does anyone have a favorite 16k*8 EEPROM ic that is common and likely to be available for a few more years?
Re: HP 54542C Scope

 

Hi Michael,

thanks for the update and sorry for my delayed response: I have
been on a trip in the Alps without access to the Internet...

The parts came in this morning and I R&R'd the LM350 and it didn't seem to have any effect on the issue, maybe reduced but maybe not.
OK, that is bad. Do you observe the noise on all channels? In my
case in 2013 I had all channels showing the same noise, see here:



I.e. turn on all channels and set them to different y-positions and
see whether the noise is correlated!

0v, and pin 3 = 5.37 volts. From reading your prior post I'm assuming something is drawing too much current as you mentioned.
Yes, I guess that this is the case. If the noise is synchronous on
all channels I bet for the supply a the prolem! In 2013 I prooved
this by supplying the -12V temporarily from an external supply and
0.5A -0.7A have been sufficient and the noise was gone with the
external supply.

HOT, interestingly, all the other rails are within specs, save the +15, which is +16.66 volts, (I'm really curious what's causing that).
My supply has more than +15V here, too.

but I see no other recourse. I can't help but think that the -12 should be loaded down a bit?!?! But it's solid at -12...
That sounds strange - in my case (and using a second oscilloscope)
I was able to see some temporal excursions on the -12V power line
as the noise was visible on the screen.

Let's see the other responses...

Erik.
Re: HP 8753B CPU issue

 

I'm sure you already considered, but the PAL was burned fresh, or swapped from a board of the same revision? ?As a programmable device, it is possible that the code in the PAL did change between board or prom revisions.

Note that I have no knowledge of that unit specifically but I just got burned by different PAL code on a different repair.

Nathan
KK4REY


On Wed, Feb 17, 2016 at 19:09, ChuckA chuck@... [hp_agilent_equipment] wrote:

?

I've been working on this problem 8753B CPU card for a few months now
with very limited results. The original problem was no video, which I
tracked down to a bad PAL 16R1 chip, replacing that got me a screen with
random lines and various flashing characters. I thought that problem was
bad DRAM so I replaced them, still no change. Watching the status lights
while changing the position of the A9CC jumper and pressing the "PRESET"
button I was able to get it to occasionally start to work, but not all
the time.

The short story is I can now get it to run every time by following
this procedure; turn the unit on with the A9CC jumper in the "NORMAL"
position, then move the jumper to the center position and press
"PRESET", then move the jumper to the next position to the right and
press "PRESET". This will display "DRAM Passed" on the screen, then move
the jumper back to the "NORMAL" position and press "PRESET", at which
time the unit will start up and operate normally as long as power is
applied.

Any change in that sequence and it will not operate. I've swapped the
PROM's into a working board and they work fine.

Anyone have any idea what is going on with this?

Chuck

--
See Early TV at:

www.myvintagetv.com
HP 8753B CPU issue

 

I've been working on this problem 8753B CPU card for a few months now with very limited results. The original problem was no video, which I tracked down to a bad PAL 16R1 chip, replacing that got me a screen with random lines and various flashing characters. I thought that problem was bad DRAM so I replaced them, still no change. Watching the status lights while changing the position of the A9CC jumper and pressing the "PRESET" button I was able to get it to occasionally start to work, but not all the time.

The short story is I can now get it to run every time by following this procedure; turn the unit on with the A9CC jumper in the "NORMAL" position, then move the jumper to the center position and press "PRESET", then move the jumper to the next position to the right and press "PRESET". This will display "DRAM Passed" on the screen, then move the jumper back to the "NORMAL" position and press "PRESET", at which time the unit will start up and operate normally as long as power is applied.

Any change in that sequence and it will not operate. I've swapped the PROM's into a working board and they work fine.

Anyone have any idea what is going on with this?

Chuck

--
See Early TV at:

www.myvintagetv.com
Re: HP 3325A What ROMS?

 

¿ªÔÆÌåÓý

John,

?

I don¡¯t know of any source of the Synertec EPROM data.? The person I helped with this problem in 2013 ultimately removed his chips and installed the two chips referred to in the link below.? IIRC, one of the problems with the ¡®direct replacement¡¯ approach was finding chips that were, in fact, direct pin for pin compatible.

?

With the ¡®two chip¡¯ approach, you wind up with a board that is ¡®original¡¯, sort of, since it was one of the ¡®original options¡¯ for the unit.? And, it is relatively straight forward, not requiring building any additional circuitry, with issues of ¡®timing¡¯, etc.

?

?

Let me know if you have any questions or if I can help.

?

Good luck.

?

Joe

?

From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
Sent: Tuesday, February 16, 2016 11:34 PM
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: HP 3325A What ROMS?

?

?

Sorry to connect up to this thread. tried to make a new one but Yahoo no
longer recognizes my id and wont let me post
new thread
Been following the 3325A threads as I think I have a ROM issue with
mine, but have looked at all the referenced
threads and cant find mine there
My printed manuals including the Hp cross references are currently
under a 4 ft pile of manuals etc after a 6 shelved cheap bookshelf
collapsed and threw everything on the floor ... had been Ok for the last
3 years, but gave up under the weight last night, so apologies for
asking stuff I may have been able to find otherwise... its over 40Deg C
in there at the moment as were having a continual heatwave her in West
Australia
and I cant even breath properly in that room.right now

3325A S/N 1748A03039 OPTION 1 Bought at local auction 5 years ago

4 X ROMS soldered in Probably Synertec (Large square "S")

U1
7941E
C51030
Hp No 1818-0702

U2
7932E
C51031
Hp No 1818 -0703

U3
8007E
C51032
Hp No 1818 -0704

U4
7952E
C51243
Hp No 1818-9705

The "5" after the C is definitely a Five, not a Y

Q: can you point me to where I can find mod info for these chips
replacements please?
Have downloaded ( start Jun 3rd 2013) 3325A collection as directed ,
but don't see anything relevant to my chip set there

Symptoms are: crazy randomized LED display constantly randomly repeating.

Previous work done:
Replaced On/Off switch
Replaced all ribbon interconnects with made up ones as originals
separated (All connections checked out OK ....big job)
Replaced a (wire wound!!) output resistor from a previous "repair" with
original HF type.
All PSU voltages correct with ripple within specs
Had been working fine until a few months ago
Thanks for your time

John
Re: Test Equipment where battery failure causes SERIOUS problems

 

The 859X series spectrum analyzers loose: band leveling offsets, attenuator corrections, and clock corrections if the memory battery dies. There is at least a procedure to copy these down from the operator interface so they can be reloaded in event of failure.?
-Kelly


On Wednesday, February 17, 2016 2:02 AM, "Peter Hansen oz1lpr@... [hp_agilent_equipment]" wrote:


?
Hello David?I think the HP 8756 Scalar analyzer?Looses all the Channel calibration data if the battery is lost. This requires?programming through a HP computer with obsolete software.
best regards Peter Hansen
?
To: hp_agilent_equipment@...
From: hp_agilent_equipment@...
Date: Tue, 16 Feb 2016 21:39:40 +0000
Subject: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

On 16 February 2016 at 21:27, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby@...> wrote:


2) HP 3457A 6.5 digit multimeter


whilst not so catastrophic, a report I read recently on one of the newsgroups from someone, said he sent a 3457A in for calibration, and the company was not happy as the failure of the battery added an hour to the calibration time. They were going to charge for this, but in the end they did not.

Just to clarify, the extra hour was not for replacing the battery - the owner had already done that. The extra hour was for the fact every range needed zeroing and setting to full scale.?



Re: HP 3325A

 

If its any consolation,I have two 3325As in regular use. One has had this same fault since I owned it and the other appears to have developed the fault in th last five to ten weeks. I cannot verify the serial numbers at this stage as Im away from the lab at present. I have been following the thread with interest.


Pete
Re: Test Equipment where battery failure causes SERIOUS problems

 

¿ªÔÆÌåÓý

Hello David?I think the HP 8756 Scalar analyzer?Looses all the Channel calibration data if the battery is lost. This requires?programming through a HP computer with obsolete software.
best regards Peter Hansen
?
To: hp_agilent_equipment@...
From: hp_agilent_equipment@...
Date: Tue, 16 Feb 2016 21:39:40 +0000
Subject: [hp_agilent_equipment] Re: Test Equipment where battery failure causes SERIOUS problems

?

On 16 February 2016 at 21:27, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby@...> wrote:


2) HP 3457A 6.5 digit multimeter


whilst not so catastrophic, a report I read recently on one of the newsgroups from someone, said he sent a 3457A in for calibration, and the company was not happy as the failure of the battery added an hour to the calibration time. They were going to charge for this, but in the end they did not.

Just to clarify, the extra hour was not for replacing the battery - the owner had already done that. The extra hour was for the fact every range needed zeroing and setting to full scale.?


Re: 8590E Video Display problem

 

I have noticed that many pieces of HP equipment have an electrolytic
capacitor that goes from the wiper of the intensity pot to ground.

The purpose of the cap is to cause the instrument to start with the
beam forced off. This protects the phosphor during those moments
while the power supplies are coming up to voltage, and various
amplifiers may be operating in out of bounds conditions.

When the capacitor becomes leaky, it can draw enough current that it
keeps the intensity turned off. The condition improves somewhat as
the instrument warms up and the capacitor charges.

-Chuck Harris

Artek Manuals manuals@... [hp_agilent_equipment] wrote:

On 2/16/2016 5:27 PM, pbbob426@... [hp_agilent_equipment] wrote:
I have an HP 8590E in which there is no video on initial power up. But
consistently, if I shut the 8590E down anytime after about 2 minutes and
turn it again, the display is perfect - until the next cold start.


Anyone have any ideas what may be causing this?
Bad cap somewhere...holding an address line down on a cold start ...then
on a warm start the cap is feeling better and lets the address line come
up faster
Re: HP 3325A What ROMS?

 

Sorry to connect up to this thread. tried to make a new one but Yahoo no longer recognizes my id and wont let me post
new thread
Been following the 3325A threads as I think I have a ROM issue with mine, but have looked at all the referenced
threads and cant find mine there
My printed manuals including the Hp cross references are currently under a 4 ft pile of manuals etc after a 6 shelved cheap bookshelf collapsed and threw everything on the floor ... had been Ok for the last 3 years, but gave up under the weight last night, so apologies for asking stuff I may have been able to find otherwise... its over 40Deg C in there at the moment as were having a continual heatwave her in West Australia
and I cant even breath properly in that room.right now

3325A S/N 1748A03039 OPTION 1 Bought at local auction 5 years ago

4 X ROMS soldered in Probably Synertec (Large square "S")

U1
7941E
C51030
Hp No 1818-0702

U2
7932E
C51031
Hp No 1818 -0703

U3
8007E
C51032
Hp No 1818 -0704

U4
7952E
C51243
Hp No 1818-9705

The "5" after the C is definitely a Five, not a Y

Q: can you point me to where I can find mod info for these chips replacements please?
Have downloaded ( start Jun 3rd 2013) 3325A collection as directed , but don't see anything relevant to my chip set there

Symptoms are: crazy randomized LED display constantly randomly repeating.

Previous work done:
Replaced On/Off switch
Replaced all ribbon interconnects with made up ones as originals separated (All connections checked out OK ....big job)
Replaced a (wire wound!!) output resistor from a previous "repair" with original HF type.
All PSU voltages correct with ripple within specs
Had been working fine until a few months ago
Thanks for your time

John
Re: Soldering recommendation

 

I read somewhere that heat is used to soften Cyanoacrylate and alcohol is used to dissolve it so that you can separate the two pieces.

On 2016-Feb-16 10:11 PM, Peter Gottlieb hpnpilot@... [hp_agilent_equipment] wrote:
I may do that. Tried the hot air, too crude even with a very small tip, and it
started softening the glue I used to keep everything stable.

Peter
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