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  1. HP-Agilent-Keysight-Equipment
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Date
Re: Manuals for an HP3456B DMM?

 

Thanks for the inputs on the issues for this meter.
I have written tools for several "R2D2" instruments. The command set is similar to the 3455A which I have already written a tool set for.
One thing that is not clear from the manual is whether it is possible to read back the instrument configuration. The 3455A has a "bag of bits" type configuration read back command, but I don't see anything like that on the 3456A. I need to spend some more time exploring the command set.
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BobH
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Re: Manuals for an HP3456B DMM?

 

I'm not sure how luck plays into programming the 3456A,
it is a very rigidly defined state machine that is well
documented in the operation manual.

The 3456A is programmed using an slightly enhanced version
of what is colloquially known as "R2D2" style.

There is a table of all commands in the operation manual,
and each command is 1 or 2 upper case ascii letters
followed by one or more ascii numbers.... syntactic sugar
is not allowed. No commas, spaces, tabs, etc... just
numbers.

What the 3456A won't do, is take long text commands, such
as "VOLTAGE", or "FILTER", or "IDENTIFY" or "IDN?", but
rather takes one or two letter abbreviations like, "V", or
"F".

Otherwise, it is the poster child for simple to program.

You do have to wait around for the meter to finish its
operations, but that is a pretty common among HPIB
devices.

The ability to calibrate most functions from the panel
next to the terminals is nice... as long as the little
10T wire wound pots are still noise free.

-Chuck Harris


On Sat, 5 Apr 2025 21:57:51 -0700 "John Kolb"
<jlkolb@...> wrote:

I love that I can calibrate them with a screwdriver rather than
stepping through software menus.

Good luck with the GPIB programming. They predate the SCPI
programming standards.

John??? KK6IL

On 4/4/2025 10:57 AM, BobH via groups.io wrote:
I picked up the meters today. They are model 3456A. Both work, but
need some cleanup. The power switch on on unit sticks on and the
front/rear terminal switch is dirty. A quick checkout shows both
reading within a few mV of my 34401A. Now I need to port my GPIB
tools to talk to them.
Re: E5052A Power On Test (3.3V Bus Supply)

 

Glad you got it fixed!
?
I did look through the program code and found references to your errors but I couldn't find an obvious cause, only ways to patch past the errors. There are some diagnostic features built into the code but I haven't really explored these and there is a debug file that gets written to if anything fails during bootup. Yours has probably overwritten with a blank file if it is working OK.
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Note that the main program code includes a simulator mode where you can install and run the program on a (Windows 2000?) PC and it simulates a fully working E5052A. It even gives a simulated phase noise response on screen that has 'moving' noise.
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However, I tried it on a couple of PCs (not Windows 2000) and it quits after a couple of seconds. This may be deliberate as there doesn't appear to be a way to manually quite the E5052 app apart from turning off the instrument. I did manage to get it to stop quitting with a crude patch but it wasn't really worth the effort.
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The pass/fail limits for the various service mode tests are stored inside a file on the HDD and I can show you where this is if you haven't already found it..
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I'm pleased you got it working, I wasn't too keen on taking mine apart again and it's packed away in storage at the moment. It isn't an instrument I will use very often, maybe a few times a year or so.
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I've got an old library plot of an E8257D PSG sig gen at 1 GHz and it agrees very closely with your plot although the vertical scaling is very different.
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I can also see the 60kHz blip from the LCD on your plot. It's inverted but it will be much more obvious (and not inverted) when you test something with lower phase noise at a 60 kHz offset. You can see it in the plot below as well.
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Re: 8495G Step ATT OPT 011 5V Cable Pinout

 

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Am 06.04.2025 um 08:00 schrieb 4X6MU via groups.io:

Hi,?
?
If anyone can pls help with the cable pinout for the 8495G Step ATT OPT 011 5V.
Service Manual Documentation is not clear or missleading, it doesn't show where the common Ground and +5V go.
?
Thanks, Ilan Yacobi 4X6MU

HP8495 Datasheet 5990-4474.pdf
HP8495 Datasheet 5990-4474.pdf

8495G Step ATT OPT 011 5V Cable Pinout

 

Hi,?
?
If anyone can pls help with the cable pinout for the 8495G Step ATT OPT 011 5V.
Service Manual Documentation is not clear or missleading, it doesn't show where the common Ground and +5V go.
?
Thanks, Ilan Yacobi 4X6MU
Re: Manuals for an HP3456B DMM?

 

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I love that I can calibrate them with a screwdriver rather than stepping through software menus.

Good luck with the GPIB programming. They predate the SCPI programming standards.

John??? KK6IL

On 4/4/2025 10:57 AM, BobH via groups.io wrote:

I picked up the meters today. They are model 3456A. Both work, but need some cleanup. The power switch on on unit sticks on and the front/rear terminal switch is dirty. A quick checkout shows both reading within a few mV of my 34401A. Now I need to port my GPIB tools to talk to them.
?
Re: E5052A Power On Test (3.3V Bus Supply)

 

Figured it out.
?
So the LT1084 arrived from digikey. I swapped U18 and U19 on the A3; no changes in LED state or boot up error.
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At this point, I had also removed PSU and removed PSU daughterboard, cleaned all the connectors and put more deoxit on the pins, and put it all back together.
So I'm sure it wasn't a power supply issue.
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There are 5 right angle male SMB connectors on the front of the A3 module. Two on the left are CH1 IF and two on the right are CH2 IF. The middle one is a 100 MHz clock.
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Looking at the layout of the A3, this is a clock input, as there are multiple clock distribution ICs which spread out to all the FPGAs and ADCs.
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So I put a low frequency directional coupler in the path of this clock and checked the coupled signal on a scope. No signal at all.
?
I then used my signal generator to inject a 100 MHz, -20 dBm clock in manually. After that, the instrument got past the original error and booted to the measurement screen!
However, it failed nearly all of the power-on tests. Strange, since the results were mostly gibberish (no actual voltage values, lots of fails on power rails that I confirmed manually).
?
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I decided to investigate the lack of 100 MHz clock. This SMB cable leads back to one of two identical local synthesize modules (A4/A5). Removed both as they are identical.?
?
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Doing some side-by-side measurements, I noticed that there was a blown surface mount fuze on the module which was responsible for the clock.
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I traced the circuit before and after, it looks like this fuze separates a switching and linear regulator locally from the power rail coming in through the backplane. There are lots of tantalum and aluminum caps, so I did some in circuit DC measurements. No sign of a blown or failed cap, and all test points measured identically between the two.
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Of course, I don't have a 1 amp SMT fuze in this size, so I had to macgyver a 5 x 20, 1A glass fuze with heatshrink and some wire to put it in circuit.?
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?
Popped the modules back in and viola, its working.
?
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No clue why the original fuze opened, as the unit seems to run normally otherwise. All power on test points are normal and measurements also look reasonable.
Example measurement of recently OEM calibrated sig gen (E8257D UNX), seems to align with specs.
?
?
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Now have to order the proper fuze and make the repair permanent.
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Cheers,
Kevin
Re: Fail over input board for the HP-5087A distribution amplifier

 

Ed,
?
Count me in, that would be a nice feature for my 5087A.
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Ron
Re: 8594E Cal Signal not Found ?

 

I had an edit failure resulting in the wrong draft being sent. (Wipes egg off face)
Re: 8594E Cal Signal not Found ?

 

Ed,
?
You are incorrect on the size.? The Intel HEX format provided at KO4BB is two bytes of ASCII to be converted to one byte of binary, plus the Intel format includes some overhead for each record (length, offset, type, checksum).? There is no compression making the encoding expansion for a binary a factor of about 2.4.
?
Ex for one of the image files:
?
? $ srec_info 8590-u6.hex -intel
? Format: Intel Hexadecimal (MCS-86)
? Data: ? 000000 - 03FFFF
?
4x 27c020 is what is needed.
?
Please check your math.
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-mark
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?
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On Sat, Apr 5, 2025 at 05:38 PM, Ed Marciniak wrote:

The files in the folder referenced are 636KB each as hex. As binary, that should be around 512KBytes each, or 4 megabits.
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I guess you could do the math on whether your two chips hold 8 megabits each.
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I don't have an 859X but I am a computer guy working backwards from my phone.
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I just saw an email pop up while writing this about 4x27c020. I think you’ll find the newer firmware is larger than the old and you’ll need 27c040 parts.
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Being the Motorola processor begins its power up by reading from the bottom of memory address range and ram typically gets located at the top, this avoids having to remap address lines, but it also facilitates swapping larger EPROMs in so long as the sockets have enough address lines to address the entire chip.
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..
Re: 8594E Cal Signal not Found ?

 

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The files in the folder referenced are 636KB each as hex. As binary, that should be around 512KBytes each, or 4 megabits.

I guess you could do the math on whether your two chips hold 8 megabits each.

I don't have an 859X but I am a computer guy working backwards from my phone.

I just saw an email pop up while writing this about 4x27c020. I think you’ll find the newer firmware is larger than the old and you’ll need 27c040 parts.

Being the Motorola processor begins its power up by reading from the bottom of memory address range and ram typically gets located at the top, this avoids having to remap address lines, but it also facilitates swapping larger EPROMs in so long as the sockets have enough address lines to address the entire chip.


From: [email protected] <[email protected]> on behalf of KB2LMN via groups.io <kb2lmn@...>
Sent: Saturday, April 5, 2025 12:17:18 PM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8594E Cal Signal not Found ?
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Well I believe I found the newest software
?
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My question is I only have 2 EPROMS in my 8594E do I need 4 or can the files be combined some how I to 2. If not I will need to pick up 2 EPROMS.
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Andrew
Re: 8594E Cal Signal not Found ?

 

Mark, great thanks I actually found 4 AMD AM27C020’s I will use them they state they have HP 859XE 95-09-14 on them. I kind of remember picking them up at a hamfest a few years ago and some digging was done to find them.?

Andrew
Re: 8594E Cal Signal not Found ?

 

That is the latest firmware on KO4BB.
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Look at the size of the four HEX files when loaded into your programmer. ?You will need (4) 27C020-150 2Mbit (256kbyte) EEPROMs to hold them all.
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The firmware doc is wrong in saying that you need (4) 1Mbit EEPROMs. ?I think it's only true for version H (95.02.21) or older. ?And if you use anything other then 2Mbit EEPROMs, you need to restrap the EEPROM socket selects (see schematic). ?Save yourself a headache and stick with 27C020-150.
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I did the same upgrade from G to L on one of my 8595E analyzers: (2) 27C020-150 to (4) 27C020-150. ?Worked fine. ?I bought (4) 27C020-150 for the upgrade and saved the old EEPROMs in case something went wrong.
?
-mark
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On Sat, Apr 5, 2025 at 01:17 PM, KB2LMN wrote:

Well I believe I found the newest software
?
?
My question is I only have 2 EPROMS in my 8594E do I need 4 or can the files be combined some how I to 2. If not I will need to pick up 2 EPROMS.
?
Andrew
Re: 8594E Cal Signal not Found ?

 

Well I believe I found the newest software
?
?
My question is I only have 2 EPROMS in my 8594E do I need 4 or can the files be combined some how I to 2. If not I will need to pick up 2 EPROMS.
?
Andrew
Re: Intermittent REF UNLOCK error message on 8591A Spectrum Analyzer

 

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Hi Anders,

?

I'm glad to hear that you were able to fix your Spectrum's 600 MHz VCXO circuit and get it working.

?

Yves

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Re: Manuals for an HP3456B DMM?

 

The 3456A is a very nice meter, and I think the only of
its sort HP ever certified as a transfer standard.

There are a couple of failures you should watch for.

First, the more desirable is the meter without the fan,
if you have a fan, it is a much older model, and I don't
know much about those.

DO NOT TOUCH ANY OF THE BOARDS WITH YOUR BARE FINGERS!

DO NOT TRY TO CLEAN PCBs, UNLESS YOU WANT TO SPEND HOURS
SCRUBBING WITH PURE 99% IPA. and even then, you may fail.

The large axial leaded filter capacitors tend to dry out,
and may need replacing. Check them with an ESR meter.
When they go bad, the meter will count erratically.

These are very high impedance meters. They will drift
when open circuit, in all but the highest DCV range.

The big reed relay that routes the ohms current tends to
get its contacts coated with something that makes it
unreliable. I usually remove a coil wire, and put a
wetting current through the contacts, and buzz them by
applying 25Hz, or so to the coil. I put a volt meter
across the contacts (mechanical, not dvm) and when the
needle gets to 50% of the wetting voltage, you are done.

10ma, with a series resistor is a good wetting current.

The front panel push switch that switches between front and
rear panel input is known to never work again, if you ever
push it. It is bound to need cleaning with some deoxit.

The trim pots that are for calibration are under the
input connector front panel, and are wire wound, and get
dirty. If you find you need to adjust them, get some
deoxit slider lube into them first.

The AC is calibrated for 1KHz, not 50/60Hz. There is a
serious noise problem at or near 50/60 hz, so that if you
put, say, 61Hz input in 60Hz land, your lower digits will
count up and down with the beat note.

If you ever find a way to fix that, please let us know!

Enjoy your new meters!

-Chuck Harris


On Fri, 04 Apr 2025 10:57:54 -0700 "BobH via groups.io"
<wanderingmetalhead@...> wrote:
I picked up the meters today. They are model 3456A. Both work, but
need some cleanup. The power switch on on unit sticks on and the
front/rear terminal switch is dirty. A quick checkout shows both
reading within a few mV of my 34401A. Now I need to port my GPIB
tools to talk to them.
Re: 8594E Cal Signal not Found ?

 

Yves thanks for sharing that info after I read the ENTIRE how to input constants section I found at the very end a work around so I’m good now. Now I’m just looking for the newest firmware version and then I’m done with this one and onto an 8591 I picked up.
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Andrew
Re: 8594E Cal Signal not Found ?

 

Mark I did get everything working last night thank to your help I appreciate it! I ran it through some tests and it passed them all so the firmware was my next leap. Fortunately I have done some chip programming so this one should be an easy fix/ upgrade for me. I looked around and can’t find the G 980615 file for upgrade purposes.
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Again thanks for sharing your expertise it would have taken me much, much longer to figure this all out on my own.
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Andrew
Re: Intermittent REF UNLOCK error message on 8591A Spectrum Analyzer

 

I am very impressed by your knowledge Yves!
?
My spectrum analyzer is fixed now - at least sort of fixed.
My fix was to replace C75, change from 3.3 pF to 2.2 pF.
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Conditions after the fix:
300 MHz VCXO is 299.922 MHz with 10 MHz Ref disconnected. When 10 MHz Ref is connected it is 300.000 MHz.
Maxed VTO_Tune (-13.27 Volt) gives VCXO of 300.026 MHz.
VTO_TUNE with connected 10 MHz Ref is -8.61 Volt (still some area left to -13.27 Volt).
CAL FREQ, CAL AMPTD and CONF TEST goes through without any problem.
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My Q12 bias voltage is 5.168 Volt so that was ok from start.
CR81 capacitor was not fitted in my unit.
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It was very fun to dig into this problem with your help!
This is the first time I use the HP spectrum analyzer - I have only used a TinySA Ultra before.
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Anders
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?
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Re: 8594E Cal Signal not Found ?

 

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I repaired an 8591A for a friend two weeks ago, and he had the same problem.

In his case, it had lost its calibration constants due to a low battery.

?

What caused the signal not found or LOCK OFF SRQ110 problem was that the units after a PRESET weren't dBm but mV, and also that the flatness data was empty...no value.

For flatness, I had entered a value of -1 for the entire band.

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After fixing these two issues, I was able to run CAL FRE and CAL AMP without any problems.

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I'm not saying this is the problem with your 8594E, but out of curiosity, do either of these two cases apply to you regarding flatness and units after a PRESET?

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Yves

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