Re: HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
Re feet there is a file for feet to make them using a 3 D printer ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Roy Thistle
Sent: 09 September 2024 17:53
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read) ? On Sun, Sep 8, 2024 at 08:40 AM, Jim wrote: missing bottom feet
Yes, they often walk away here... hide amongst a large number of friends... in an un-labeled? cardboard box somewhere... and eventually...enjoy the ride... to their final home... the dump. There are models for them... and they can be 3D printed...by the local teenager... and if all you are interested is in functionality... from a distance... they look reasonably similar. The bright orange PETG print threw me off at first... but, one can't see it when the unit is on the bench... and the 'feet' keep the case from contacting the bench... which is a 'no no' here. But of course... nothing beats the bone fides. You can always find those on Ebay, for 10.00 to 20.00 USD + plus 50.00 USD shipping. I think scrappers, junk magnets, and metal hounds, keep the feet, and 'throw' the instrument away.
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Re: HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
On 9/9/24 12:53, Roy Thistle wrote: missing bottom feet
Yes, they often walk away here... hide amongst a large number of friends... in an un-labeled? cardboard box somewhere... and eventually...enjoy the ride... to their final home... the dump. Wow, Roy. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
On Sun, Sep 8, 2024 at 08:40 AM, Jim wrote:
missing bottom feet
Yes, they often walk away here... hide amongst a large number of friends... in an un-labeled? cardboard box somewhere... and eventually...enjoy the ride... to their final home... the dump.
There are models for them... and they can be 3D printed...by the local teenager... and if all you are interested is in functionality... from a distance... they look reasonably similar.
The bright orange PETG print threw me off at first... but, one can't see it when the unit is on the bench... and the 'feet' keep the case from contacting the bench... which is a 'no no' here.
But of course... nothing beats the bone fides.
You can always find those on Ebay, for 10.00 to 20.00 USD + plus 50.00 USD shipping.
I think scrappers, junk magnets, and metal hounds, keep the feet, and 'throw' the instrument away.
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Re: 8566B attenuator removal
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Some Hp 8568b attenuator repair guidance, with photos, can be found here:
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rick
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Re: E4438c display problem, controler memory location please
I am not sure this covers the 4438B specifically, but the CLIP for the 4400 family shows that they use the 66510 LCD controller, at U607.? This controller uses a dedicated 514260 256k x 16 DRAM, at U610-A.
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Hope this helps,
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-mark
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Re: HP 8568B from hell to Heaven... a restoration story!
The RF unit
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I decided to first test the RF unit and leave the display for later. The RF unit was miraculously complete with all the boards. However, several screws and the plastic covers protecting the boards were missing. Additionally, the entire cooling fan assembly was not present. The tuning knob was missing from the front panel (fortunately i have some spares), and the covers were, of course, not there.
First, I installed a temporary fan to avoid overheating the unit, hoping to find the original one in the future. Then I turned on the unit and crossed my fingers...
The first power-up didn¡¯t go well, no image on the screen, and the right red LED was on. The CPU board showed the fourth LED lit during the self-test, indicating an I/O error. The manual explains the possible causes of the problem: it could be two faulty PALs or many other reasons. While I was inspecting the device, I noticed that the I/O board wasn¡¯t properly seated in its socket. I proceeded to remove, clean, and reinsert the board, and on the next power-up, I no longer had any errors, and the RF unit was alive!
Clearly, the backup battery was signaling depletion, so I replaced it. However, a big issue remained: there was no sweep, so the trace was stuck. I checked the amplifier board and noticed that someone had switched the input and output cables. Incredible... Once they were corrected, we had a perfect sweep.
At this point, I ran the first calibration, feeling quite confident, but unfortunately, it failed, even after adjusting the calibrator and frequency align to -10 dBm. I noticed that the calibration failed when it started exercising the attenuator. Indeed, there were some attenuator positions that didn¡¯t work.
I manually exercised the attenuator, and after 3 or 4 switchings, it started working perfectly again. There was clearly some oxidized contact. I relaunched the calibration, and this time, everything went well. The RF part works perfectly.
After testing some sample signals, I loaded the HP DLPs via GPIB and declared the repair finished...
Now it¡¯s time to move on to the 85662A¡
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Re: 8566B attenuator removal
Well, I've ordered a range of sizes just to be on the safe side. Unfortunately they won't be arriving any time soon (yeah, China) so there won't be any updates for at least a week I'm afraid. Anyway, now I've got the attenuator out, this thread's objective has been achieved, so I'll begin a new one for the actual overhaul process when those parts are finally here.
Many thanks for your assistance! :)
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Re: HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
In message < [email protected]>, Jim via groups.io <james_buttons@...> writes Thanks Dave.
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I'll look into that next. During my initial testing I did look at
the freq. output of the oscillator and I didn't see anything that
looked outrageous re: actual vs. setting, but I didn't run the math
to see if in spec. I the cases where the input LED was on,
sometimes the oscillator freq was spot on and other frequencies
where the LED was on freqs. seemed off from spec, but not too far
off. I think it may be a little bit of both - notch filter center
freq. being off in some cases, oscillator freq. off in others.
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I looked through the schematic at the section for the monitor
output and it's a simple path from the main meter circuitry (which
appears to be working) - just a resistor, fuse and then the
isolation relay. I hear the relay get activated/deactivated, so
once I have the unit open again I will probe that path and see
where the signal stops. I am hoping that it's just the 0.062A fuse.
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I am going to let the unit "bake" for a week or so. After 24 hours
the freq. that starts requiring the vernier is now down from 3.5
KHz to 3.3 KHz.
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Did I read somewhere where HP did not include the schematic for the
339A's oscillator itself in the service manual?
? I think it is there are some versions for this unit online here and there had one for years very reliable;! Whilst your at it make sure of you change the power supply caps this improved the distortion reading on mine by a decent amount supply ripple i suppose?>. -- Tony Sayer
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Re: hp 5480A Signal Analyzer I/O Connector Question
I have both the user manual (in paper form) and the service manuals that are scans from microfiche:
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Christopher
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Re: hp 5480A Signal Analyzer I/O Connector Question
As this is a relatively old instrument as far as bus/remote control is concerned, I am wondering if the connectors are possible BCD format for local i/o. ? Presumably this is documented in the main user manual? Do you have that? Regards Nigel ?
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From: [email protected] <[email protected]> On Behalf Of Christopher Tucker via groups.io
Sent: 07 September 2024 13:09
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] hp 5480A Signal Analyzer I/O Connector Question? I am working with an hp 5480A Signal Analyzer, especially its connection ports on the rear, as a programming exercise with a RaspberryPi: Concerning 18 and 19: The manual says J18 is something called a?Correlation Synthesizer while J19 points to an I/O Connector hp 5495A Would anyone have any information on either of these, what they consisted of?
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Re: HP 5342A blowing fuses on switch on
Jack,
I would check CR1 and CR2 (the bridge rectifiers) 1st. One might be shorted. Assume you have a DVM and know how to do this.
(with the board removed of course)
Mark
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My 5342A freq counter has started blowing fuses on switch on.
I removed the A19 board which just left the filter, fan and oven transformer in circuit. No blown fuse and the fan runs.
Replaced the A19 board and BANG.
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I am seeing a kit of PSU boards for a 5343 which, by the board numbers, look the same.
Should I just get these 3 and replace then all of does anyone have some insight?
I do not have an isolation transformer and am very hesitant to work on this while it's connected to the mains.
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Thanks
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HP 5342A blowing fuses on switch on
My 5342A freq counter has started blowing fuses on switch on.
I removed the A19 board which just left the filter, fan and oven transformer in circuit. No blown fuse and the fan runs.
Replaced the A19 board and BANG.
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I am seeing a kit of PSU boards for a 5343 which, by the board numbers, look the same.
Should I just get these 3 and replace then all of does anyone have some insight?
I do not have an isolation transformer and am very hesitant to work on this while it's connected to the mains.
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Thanks
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Re: HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
Thanks Dave.
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I'll look into that next. During my initial testing I did look at the freq. output of the oscillator and I didn't see anything that looked outrageous re: actual vs. setting, but I didn't run the math to see if in spec. I the cases where the input LED was on, sometimes the oscillator freq was spot on and other frequencies where the LED was on freqs. seemed off from spec, but not too far off. I think it may be a little bit of both - notch filter center freq. being off in some cases, oscillator freq. off in others.
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I looked through the schematic at the section for the monitor output and it's a simple path from the main meter circuitry (which appears to be working) - just a resistor, fuse and then the isolation relay. I hear the relay get activated/deactivated, so once I have the unit open again I will probe that path and see where the signal stops. I am hoping that it's just the 0.062A fuse.?
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I am going to let the unit "bake" for a week or so. After 24 hours the freq. that starts requiring the vernier is now down from 3.5 KHz to 3.3 KHz.
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Did I read somewhere where HP did not include the schematic for the 339A's oscillator itself in the service manual?
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JB
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Re: 8566B attenuator removal
The sizes I¡¯ve seen for watches weren¡¯t 1/2mm cross section. They were thicker like 0.6mm (1.0 ID/2.2OD or something like that).
The proper size isn¡¯t that hard to come by.
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Hi, O©\rings are 2mm OD and 1mm ?D. Commonly used to seal the stem on wristwatch winders. Just be wary of cheap imports made from inferior materials!
On 8 September 2024 17:45:38 BST, "Jinxie via groups.io" <paul666@...> wrote:
I have now extricated the attenuator from the guts of the analyzer (see picture). Can some kind soul point me to the disassembly instructions for this thing? I've also included a photo of the spare attenuator I have which I may have to cannibalize to repair
the original one. Also, if anyone has a rough idea of the size of the o-rings I might encounter later on, that would be helpful. I have quite a selection of o-rings 'in stock' here.
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J.
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Re: 8566B attenuator removal
If the problem is with the o-rings (likely scenario), you will not be doing anything to the attenuator cards. You will not be removing them unless they have been overloaded. The cards are made of thin film resistors on saphire substrates.They don't deteriorate unless overloaded.
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For o-ring replacement, you will have to carefully unhook the plastic plungers from the leaf springs. You will need some fine tools like tweezers or similar to manipulate the plungers out of the slots in the springs. The o-rings are mounted on these plungers. Then, you will put all that back in. A low power microscope or watchmaker's loupe would help. Before you start the extraction of the plungers, study the layout and understand why the rings are there. Exercise the plungers by hand to see how the mechanism works. If you don't see a ring, it may have cracked and fallen off. Compare to the neighboring section to see where it should be. The most important thing is to not bend the springs past their elastic limit while dealing with the plungers.
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Vladan
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Re: 8566B attenuator removal
Okay, many thanks indeed for all the info and pointers. That lot should set me in good stead for the task ahead, which I'm not really looking forward to as it seems to require a good eye and steady hand - neither of which I'm blessed with!? I really don't want the bench fully occupied with 'stuff' as it currently is until next Sunday, so will attempt this repair by making time during the week and pray for no hitches. I'm just hoping it's nothing terminal. Just out of curiosity, what material are these pads made from? I gather they can be a bit brittle and fragile. Were they like that from new or is it just another aspect of the age of this analyzer?
Anyway, ludicrously late here in my part of the world now so time for some shut-eye, methinks..
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Re: 8566B attenuator removal
Jinxie, I made a mistake, the 8566 attenuator has four sections, not three. I may have mixed it up with the 8568 attenuator. A 40dB attenuator card with good return loss to 22GHz is difficult to make, so the 8566 uses two 20dB cards to get 40dB plus another 20dB card to get to 60dB. The remaining card is 10dB. Your numbers show that one of the 20dB stages in your attenuator never bypasses.
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The 8566 attenuator you have (85660-60121) may possibly also be found under the following part numbers. This is from some old notes I have, verify before buying anything.
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33321YH
5086-7814
5086-6814
33321RF
and possibly 85660-60304
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The reason for all these numbers is that HP sold parts to the outside world, as well internally from division to division. Also, each 8566 (and 8568) attenuator was supplied with a PROM containing calibration data for attenuation for each stage. Don¡¯t worry about that PROM, the corrections are of very limited use. The standard 33321 is the same hardware without the PROM.
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Your 8495K uses either 24 or 5V for switching. It should have a label somewhere on it showing which. Option 024 is 24V and option 011 is 5V. Default is Opt. 024, but you should check what you have.
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The disassembly instructions were referenced in a recent post:
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This writeup may also exist in the files section of this forum.
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In a few words, there are two compartments. One consists of the solenoids, the other is a channel with the attenuator cards and leaf springs. You start out by removing the end plate held in place with four socket screws. This is the end plate that is opposite from the one with the control line connector. The screws are often hidden by a decorative cover plate which is lightly glued on. Once you remove the end plate, you can slide off the U-shaped metal cover. Don¡¯t try to pry it off by putting a screwdriver into the seem on the side, that¡¯s not how it was designed to be opened.
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After you remove the solenoid cover but before you open the rf side, check visually that the solenoids are moving by changing attenuation via the front panel keys.
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The RF block is opened by removing the screws you see around and under the label. This is the area where you will be doing most of the work. Keep this area free of lint. Be extremely careful to not deform the leaf springs that act as contacts. They are easily bent and ruined. You will have to stress them a little while unhooking the plungers which have the o-rings on them. Maybe the o-rings are still ok, in which case you don¡¯t have to risk damaging the springs. You can inspect the o-rings without removing the plungers. The o-rings are 0.039" ID x 0.024" hydrogenated nitrile rubber, 80 durometer, shore A.
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Vladan
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Re: 8566B attenuator removal
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Re: 8566B attenuator removal
Hi, O©\rings are 2mm OD and 1mm ?D. Commonly used to seal the stem on wristwatch winders. Just be wary of cheap imports made from inferior materials!
On 8 September 2024 17:45:38 BST, "Jinxie via groups.io" <paul666@...> wrote:
I have now extricated the attenuator from the guts of the analyzer (see picture). Can some kind soul point me to the disassembly instructions for this thing? I've also included a photo of the spare attenuator I have which I may have to cannibalize to repair the original one. Also, if anyone has a rough idea of the size of the o-rings I might encounter later on, that would be helpful. I have quite a selection of o-rings 'in stock' here.
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J.
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Attachments:
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Re: HP 339A Distortion Test Set repair/refurbish (hamfest find) (long read)
I had this problem too, ten or so years?ago when I got my 339A.? The notch filter's lock-in range doesn't quite overlap?with the oscillator.? I don't remember exactly what I did but I think I bent the oscillator so it was centered with respect to the filter,
by tacking on caps or resistors on the troubled ranges on the A1 oscillator board.? Looking at the schematics today, I see that the A4 notch filter board has trim-pots for filter center frequency and null.? I don't know if I missed that, or was the filter
okay and the oscillator off?? Anyway, there's a place to start.
HTH,
Dave Wise
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Hello All,
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As a possible opportunity to upgrade my? test bench's HP 333A, I recently obtained a HP 339A distortion analyzer of unknown heritage, but very late serial number.
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Physically, not in too bad shape, all things considered:?
- missing bottom feet (not unusual, I suspect - probably was rack mounted) - I would be interested in finding these, if anyone knows of a source (new or used)
- missing end cap for input knob, otherwise all knobs complete (and not broken!)
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- Cleaned up well, internal inspection didn't reveal any previous obvious "tinkering", looked clean. Powered up and went through basic testing (using internal oscillator), seemed to mostly work but with the following observations:
1) Output monitor completely dead (not too worried about this yet)
2) Using the internal oscillator (1V output), for frequencies below ~3.5 KHz, the Freq. Input LED (counter clockwise) illuminates. I can extinguish the LED by moving the frequency vernier knob off of the "calibrated" detent position. If I do this, then
all of the lower frequencies are reported to be in the notch filter's range and autoset works under this condition, depending on the actual frequency the vernier knob has to be set anywhere from just off the detent to about 2 o'clock max. As frequencies go
lower than 3.5 KHz, the vernier has to be turned more CW. I've tried various voltage output settings (3, 0.1, .03) and the above behavior doesn't change as far as I can determine. Reported distortion values seem reasonably close (if not in,) to spec.
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What I've done so far:
- carefully deoxit only the metal contacts on all wafer switches (yes this took a while)
- re-seated the one board in a connector
- re-seated all cable and connectors
- loosened, re-tighted all mounting screws
- supplied missing endcap for input knob (my HP8640B parts bin had exactly one knob with the right cap size & color - from the output attenuator's center variable control, I believe)
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I am going to leave the unit powered up for a couple of days, it seemed like the longer it was on, the lower I could set the frequency and not have to use the un-calibrated vernier setting (capacitors reforming??) and see where it's at.
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- I have not compared it to my HP 333A yet, but I have hooked up a couple of other sig gens that I have just to see its operation, results seemed reasonable
- Other than the output monitor being dead, it seems like it just might need an alignment/calibration
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I have some equipment (HP pulse generator, scopes, freq. counters, etc.), but nothing calibrated by a lab, just a semi-serious hobby for me - testing/repairing my own stuff.
I have not looked at the supply rails with a scope yet, I have looked at the output - looks like a nice sine wave.
I will review the schematic for the output monitor, but I am not hopeful if it turns out to be an active device (finding replacement transistors are pretty much unobtanium nowadays, it seems).
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Suggestions , opinions on where to go next?
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sorry for the TL;DR
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Thanks,
Jim
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I gotta say, I just love seeing the gold PCB traces on this era's equipment - no tin-wiskers here! I smile every time I open up this type of equipment.
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Paul Bicknell
Dave McGuire
Jinxie
Christopher Tucker
Jack