开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. HP-Agilent-Keysight-Equipment
  2. Messages
Expanded Topics Messages
Date
Re: HP6209B component location layout

 

Just FYI, you can use the (much shorter) www.hpwiki.org hostname in that URL.

-Dave

On 3/29/25 19:02, Hugh Gilbert via groups.io wrote:
I think you will need to select R38, (~30k) section 5-45, it sets the meter zero by canceling the programming current that passes through the current sense resistor. R53,(3k) may need to be changed also.
Check here for a manual with schematic.
<>
Hugh Gilbert
Hugh Gilbert
On Sat, Mar 29, 2025 at 4:52?PM Alex via groups.io <> <hpagilentgroup@... <mailto:[email protected]>> wrote:
Correction to my previous post: meant to say MINIMUM OUTPUT VOLTAGE
after adding the 47K resistor in series with R10 is about 160V,
maximum output is still about 320V.
I am checking some voltages around the current meter circuit: the
-3V shown on the schematic to be present at one side of R38/R53
measures only -2.29V. Same value at the cathode of CR8 in the bias
supply where this voltage originates. Cathode of CR7 has +1.77V.
CR7 is a 1N4830 "stabistor" 2.4V @ 100mA. Guessing some sort of
reference voltage or early zener diode. On the other hand CR8 is
listed as 1N3828 and seems to be a regular silicon small signal
diode. The way they are connected in series in the bias supply (for
among others temperature stability) I would expect the -3V output to
be the sum of the CR7 voltage, plus about 0.6-0.7V additional drop
of CR8, so indeed about 3V. But in real life CR8 seems to have a
drop of only 0.5V as measured, so do I have a bad CR7 that has gone
low from the original 2.4V to only 1.77V?
The other bias supply voltages: +43V is at +37.5V, and the +16V is
correct at +15.98V.
And at the reference regulator, the +6.2V (33) measures 6.43V, the
+12.4V (37) measures 12.66V, and the -6.2V (31) measures -6.22V.
All voltage readings referenced to +S (same as positive/red output
binding post with correct rear jumpers in place).
All other rear jumpers where also verified earlier to be in the
standard configuration as shown on the schematic.
--
Dave McGuire, AK4HZ
New Kensington, PA
Re: odd HP83651A error

 

Many thanks for your feedback! What was the problem with yours? A broken data line? Why exactly 100MHz shift?
Or is some YIG lookup table messed up so it locks to the wrong harmonic? How did you get it fixed?
?
Tom DG8SAQ
Re: odd HP83651A error

 

Hi Tom,
I got same problem few years ago on my 83630B. The faulty module is the low band module on the RF deck at the far end opposite to the output RF connector.
Re: PCB CAD used and/or sold by HP ?

 

Here is a link to EGS and some history.?
?
https://www.hewlettpackardhistory.com/item/a-new-dimension-to-design/
odd HP83651A error

 

Hi folks,
?
my 8510C system recently developped an unlock error, so I have checked the source HP83651A first.
It turns out, that the source output below 2,4GHz is exactly (to the Hz) 100MHz too low, while above 2,4GHz it is spot on.
Also, the 8510C works fine above 2,4GHz.
Has ever anybody seen such a strange problem? Any ideas what could cause this?
?
Tom
Re: PCB CAD used and/or sold by HP ?

 

Believe it was HP EGS...Engineering Graphics System , ran on series 200 and 300 and recall
a package running on the HP 9816 desktop.?
Re: Tricks and thoughts about the 3457A battery

 

David,

everytime I walk past the delivery section in my company I wonder what "sending from and to" of these quite sensitive instruments will do to the calibration. There are always some instruments sitting on the shelfs waiting to be picked up for calibration. Naked, not packed in some special purpose container or such. If I was the instrument :-) I would prefer having me calibrated on-site, with nothing more than a trolley to be put upon and back in the rack when finished.

cheers
Martin
Re: Tricks and thoughts about the 3457A battery

 

On Sun, 30 Mar 2025 at 17:00, Joel Setton via <setton=[email protected]> wrote:
I did it ! I replaced the memory battery in my 3457A.
?
My used 3457A was built in the late '80s and still had its original lithium battery, with a 1989 date code on it. This battery obviously needed replacement.

Another option is to ignore trying to save the calibration constants, replace the battery and send it to Keysight and let them calibrate it. Then it will be as good as you will get it. I did that, and they replaced the battery. There were before and after measurements - they made no attempt to save the constants. So everything was better after calibration. In contrast if you send it there are calibration constants about right, if it's in spec they will not adjust it. In contrast, by putting them all wrong, everything needs adjustment.?
Re: Repair HP3455A Multimeter

 

Hi have a pdf from the flowcharts, group B schematics and the groupB service excerpt.

HP3455A_groupB_Schematics.pdf
HP3455A_groupB_Schematics.pdf
HP3455A_groupB.pdf
HP3455A_groupB.pdf
HP3455A_flowcharts.pdf
HP3455A_flowcharts.pdf

Re: Tricks and thoughts about the 3457A battery

 

"Joel Setton via groups.io" <setton@...> writes:

Hello Martin,

The EPROM idea is interesting, I have explored it but I don't think it
could work. The main issue is that the 8Kbyte RAM
chip which holds the calibration data (TC5564APL-15) is also used to
store the processor stack, firmware variables,
user's memorized measurements etc.

From the schematic, we know the RAM is used as follows :
- Calibration RAM data is from 0040 hex to 01FF hex with a special
hardware mechanism to prevent accidental overwrite of
this area.
- General storage RAM (processor stack, miscellaneous variables, user
measurement FIFO etc) from 0200 to 1FFF.

.... In summary, replacing the RAM chip with an EPROM would not
work. One (strong) reason is that the processor stack
and RAM storage would not be writable.
Using an FRAM might be a possible solution. A quick search showed that
there's a FM1608B vom Cypress - 8Kx8 and available in DIP.
Re: Looking for documentation on 4263A LCR meter

 

Hi Jared,
?
I had a check - no info on this instrument
?
Peter
Re: Tricks and thoughts about the 3457A battery

 

Hello Razvan,
?
You are right, the original battery has 1 pin on the (-) end, and two pins on the (+) end. However, I found that the PC board has three plated holes on the (+) side including one in the middle, which makes it perfect for a standard battery holder with 2 wires. Please see the attached pictures.
?
Have a great day !
?
Joel

battery_-2048.jpg
PCB_-2048.jpg

Re: Tricks and thoughts about the 3457A battery

 

Hello Martin,
?
The EPROM idea is interesting, I have explored it but I don't think it could work. The main issue is that the 8Kbyte RAM chip which holds the calibration data (TC5564APL-15) is also used to store the processor stack, firmware variables, user's memorized measurements etc.
?
From the schematic, we know the RAM is used as follows :
- Calibration RAM data is from 0040 hex to 01FF hex with a special hardware mechanism to prevent accidental overwrite of this area.
- General storage RAM (processor stack, miscellaneous variables, user measurement FIFO etc) from 0200 to 1FFF.
?
?.... In summary, replacing the RAM chip with an EPROM would not work. One (strong) reason is that the processor stack and RAM storage would not be writable.
?
Cheers,
Joel?
Re: Tricks and thoughts about the 3457A battery

 

开云体育

Congrats!!
Ing. Patricio A. Greco
Taller Aeronáutico de Reparación 1B-349
Organización de Mantenimiento Aeronáutico de la Defensa OMAD-001
Gral. Martín Rodríguez 2159
San Miguel (1663)
Buenos Aires
T:?+5411-4455-2557
F:?+5411-4032-0072

On 30 Mar 2025, at 18:00, Joel Setton via groups.io <setton@...> wrote:

?
I did it ! I replaced the memory battery in my 3457A.
?
My used 3457A was built in the late '80s and still had its original lithium battery, with a 1989 date code on it. This battery obviously needed replacement.

Unfortunately, the battery is soldered to the processor PC board and provides permanent Vcc for a low-power CMOS SRAM chip which holds the multimeter's calibration constants. In other words, interrupting the SRAM supply would result in the loss of calibration data.

Thus, the battery must be replaced while the 3457A is powered up. This is a bit of a nail-biting experience, but it can be done. One useful trick I used is to prepare a cardboard shield which covers the CPU board and protects it from any solder drops and shorts, while allowing access to the battery. And of course the soldering iron must be floating.
?
Replacement batteries in the original size (lithium BR 2/3AA with solder pins) are still available for a few dollars, but I chose to install a slightly different battery, a Tadiran SL750 which has a 1/2 AA size, for which sockets are available. Using a socket means that in 10 years, the next battery replacement will be easier : with the multimeter powered up, just pop out the old battery and insert a new one. Another advantage is that 1/2 AA lithium batteries are very easy to find, there's a good chance that your local supermarket has them.
?
Now I'd like to share some thoughts and questions about this battery. As we all know, lithium batteries have a long, but finite life. Even though the current drain on the battery is less than 0.2 uA at room temperature, at some point in time the battery will die.
I read the 3457A user and service manuals, but I couldn't find a single mention of the battery. Nothing about battery life, no instructions on how to replace it, even nothing that says "contact your nearest HP sales office". To me, this doesn't make sense, especially when considering that this multimeter was introduced in 1986, at the time of the "old HP" which produced high-quality instruments, not expendable stuff. I could only think of a few possibilities :
?
- Maybe the engineers at that time believed that lithium batteries could last forever ;
- Or they thought the multimeter would be scrapped when the battery runs out, or before it does ;
- Or they decided that if a multimeter loses its calibration data because of a dead battery, it should be returned to HP for battery or processor board replacement followed by re-calibration. That's an expensive proposition.
?
None of these options make any sense to me in the context of the "old HP".
Further thoughts and comments will be most welcome !
?
Joel?
<cardboard_shield.jpg>
<All done.jpg>
Re: Tricks and thoughts about the 3457A battery

 

Hi Joel,

Since you're able to read out the contents of the RAM, would it be possible to write it to an EPROM and swap it?
I never use the save and recall commands... could this work or will it refuse to start up? Advantage would be to never bother with batteries again.

Just a firther thought, as I have the same DMM but did not yet even look inside :-/

cheers
Martin
Re: PCB CAD used and/or sold by HP ?

 

Back in the 80s, Mentor Graphics' CAD tools ran on HP-UX workstations. Perhaps that is to what he was referring.

DaveD
KC0WJN


On Sun, Mar 30, 2025 at 15:24 Ulf Kylenfall via <ulf_r_k=[email protected]> wrote:
?
Some time ago I had a discussion with a friend over old times circuit board design.
He referred to where he worked where they used to do manual design using black tape and
transparent films. "The layouts were beautiful but difficult or even impossible to modify".?
?
Then "We got a CAD-system from HP" and it all changed.
?
I am unfamiliar with CAD-systems created by and/or sold by HP and what happened to that product.
Anyone that can shed some light?
?
Cheers
?
Ulf Kylenfall
SM6GXV
Re: PCB CAD used and/or sold by HP ?

 



On Sunday, 30 March 2025, Ulf Kylenfall via <ulf_r_k=[email protected]> wrote:
> ?
> Some time ago I had a discussion with a friend over old times circuit board design.
> He referred to where he worked where they used to do manual design using black tape and
> transparent films. "The layouts were beautiful but difficult or even impossible to modify".?
> ?
> Then "We got a CAD-system from HP" and it all changed.
> ?
> I am unfamiliar with CAD-systems created by and/or sold by HP and what happened to that product.
> Anyone that can shed some light?

ISTR using something similar in the early 80s. I suspect it might have been a Racal Redac CAD package using HP terminals for display. The terminals had a more widescreen aspect ratio than VT100s, and could draw lines well.

I haven't spotted a decent reference to all that.
Re: PCB CAD used and/or sold by HP ?

 

"Ulf Kylenfall via groups.io" <ulf_r_k@...> writes:


Some time ago I had a discussion with a friend over old times circuit board design.
He referred to where he worked where they used to do manual design using black tape and
transparent films. "The layouts were beautiful but difficult or even impossible to modify".

Then "We got a CAD-system from HP" and it all changed.

I am unfamiliar with CAD-systems created by and/or sold by HP and what happened to that product.
Anyone that can shed some light?
While working on emulating HP9000/300 i've read about "HP Engineering
Graphics System", but don't know how much use it had.
Re: PCB CAD used and/or sold by HP ?

 

The system I remember from the early 1980’s was SCICARD from Scientific calculations. I think they were based somewhere near Rochester, NY.?
PCB CAD used and/or sold by HP ?

 

?
Some time ago I had a discussion with a friend over old times circuit board design.
He referred to where he worked where they used to do manual design using black tape and
transparent films. "The layouts were beautiful but difficult or even impossible to modify".?
?
Then "We got a CAD-system from HP" and it all changed.
?
I am unfamiliar with CAD-systems created by and/or sold by HP and what happened to that product.
Anyone that can shed some light?
?
Cheers
?
Ulf Kylenfall
SM6GXV
101 - 120 of 150724