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Re: HP 3403C True RMS Voltmeter display fault
The other one ooks just as weird but is healthy according to the chinese component tester.
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Are there guidelines on HP capacitor replacements? Such as caps that never/very rarely fail and those who absolutely always do?
I want to recap this unit to keep it. It's not calibrated anymore of course but it's so great. Quality long life capacitor are expensive, I don't want to replace what does not need to be.
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Thanks, Arnaud. |
Re: HP 3403C True RMS Voltmeter display fault
On 3/2/25 18:17, AArnaud via groups.io wrote:
It is indeed a Tantalum capacitor, from the Kemet T110 series. <> From my research that would be T110B226K015AS. It's expensive.Wow. I have *never* known one of those capacitors to fail. I replace dipped tantalum capacitors all the time, but never one of those! -Dave -- Dave McGuire, AK4HZ New Kensington, PA |
Re: HP 54512B (pair) repair
Razvan, Thank you very much, this is very helpful.? I've managed to rig a load - I had a couple of 1ohm/10W Vishay RS10s (bulletproof, in my experience), and it looks like the -12V rail is MIA because of something going on in the PS. If I can confirm?this, this would be great news (as opposed to tracking some failed tantalum decoupler or something else on the main board....).? Radu.? On Sun, Mar 2, 2025 at 2:51?PM Razvan Popescu via <yo8ryr=[email protected]> wrote: Hi Radu, |
HP8510C CalKit file .CK_ format
Hi there,
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I'm trying to generate the calkit file CK_ programmatically instead of punching them in various GUI based CalKit manager.
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Basically, I'm doing my homemade open and slot standards and characterize them to use as poor man's Calkit for non-critical measurement to reduce the wear and tear on my expensive Cal Kit.
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Manually entering the polynomials and class assignments in the VNA CalKit manager is very slow and painful. I'm trying to generate it a C program so that I can send it to my 8510 either by GPIB or floppy disk but I can't find the format of the 8510 CK_ file.
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Does anyone know?
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Regards,
Calvin |
Re: HP 54512B (pair) repair
Hi Radu,
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I think the PSU in all 545xx series was made by Boschert Inc. and someone already reverse engineered it. I attached the file. I hope it helps. Regards, Razvan On 02/03/2025 23:33, Radu Bogdan Dicher via groups.io wrote:
Going back to my -12V rail issue, the SM advises loading the 5.20V rail |
Re: HP 54512B (pair) repair
Going back to my -12V rail issue, the SM advises loading the 5.20V rail with a 2ohm/25W resistor. The only way I can put something similar together with what I have at hand is using these dummy loads I am using when repairing audio amplifiers, which are a pair of 8ohm/100W non-inductive resistors. By paralleling?them I can load the 5.20V rail with a 4ohm resistor.? What are some thoughts regarding whether this would be a suitable load for the PS? I think the PS just needs a low ohmic load of sufficient dissipation capacity and it should crank itself up to nominal, but maybe there's an aspect I'm overlooking.? Thank you, Radu.? On Sun, Mar 2, 2025 at 1:52?PM Radu Bogdan Dicher via <vondicher=[email protected]> wrote:
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Re: HP 54512B (pair) repair
One of the two scopes is completely disassembled - head exploding emoji - and I have the old battery desoldered after confirming?it's fully depleted.? I enclose pics with what I'm using for replacement. I probably would have been fine going with a 2032 type, but the 2430 I ended?up fitting just right (maybe a bit snug), and the pins of the holder actually match the PCB eyelets. So all is good.? I couldn't figure out what exactly was the original battery model, as it's not legible even after removing the top tab, but its diameter is a bit over 23mm.? I think this should work OK. Back to the?actual troubleshooting now! Radu.? On Fri, Feb 28, 2025 at 6:21?PM Roy J. Tellason, Sr. via <roy=[email protected]> wrote: On Thursday 27 February 2025 04:09:31 pm Radu Bogdan Dicher via wrote: |
Re: E5052A Power On Test (3.3V Bus Supply)
Watching this subject with interest.? Leo, you may want to check out OEWaves, Synergy Microwave, and Holzworth Instrumentation (now part of Maury Microwave) for ultralow PN sources and Rohde & Schwarz, OEWaves and Holzworth for measurement instruments.? Also, there are several source mfrs making sapphire resonant cavity oscillators.? You probably already know about these companies, but throwing the names out there just in case. Microchip (was Microsemi, was Symmetricomm, was Ball Efratom; correct me if I got that progression wrong) as well. I bought one of your GPSDO models a few years ago; it's great!? Looking forward to getting one (or more) of your pulsers at some point. I'm working on a synthesizer myself based on a long spool of optical fiber to get the ultralow phase noise.? The tradeoff is sidemodes, which are spurs in the microwave output.? I have an idea for a way to knock those down.? My goal is a low SWaP-C synth mainframe in a 3 rack unit box that can be expanded from 1 to 8 outputs DC to 18 GHz or so.? I just don't have the room for multiple 4 RU boxes (HPAK 8340, 8662, etc.)? Stay tuned! Jim Ford Laguna Hills, California, USA
On Sunday, March 2, 2025 at 06:41:24 AM CST, jmr via groups.io <jmrhzu@...> wrote:
I don't know if this helps, but I dug out the most recent Keysight calibration certificate for this E5052A and there is a noise floor test done at 70 MHz with correlation set to 1.
I'm not sure what is involved with this test or at what power level it is run at but the numbers for the noise floor seem to be very good! I don't have anything here that can replicate this test although I could probably design a low noise LC oscillator that could get close at a 1 MHz offset. ? I generally design wideband single loop synthesisers up at VHF through UHF and the E5052A is easily good enough for stuff like this. ?
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Re: HP 54512B
I don't believe at this point HP was providing component-level Service Manuals anymore. I'd love to see one and prove myself wrong, though. Radu.? On Mon, Sep 6, 2021 at 3:01?PM <byterock@...> wrote: Ok looks like they have added a few things since the last time I was there.? No schematic but a block diagram and trouble shooting guide unfortunetly my problem is there but in classic new-age electrinics it says 'Replace A1'? A1 being the main Circuit board. d'ho |
Re: HP 8660B/86602B developed output stability problem, getting-started suggestion(s) request
Gary, WB2UAQ --- the advice to make adjustments while the board(s) are enclosed is right on (seeing the solenoid coil on the VCO board helped me see why toroid inductor self shielding property is helpful!
I still could not measure any (filtered/smoothed) voltage at or above 0 (section 5.33 begins by having the tech adjust A19R3 or A19R9 - not sure why "or" - on the VCO board to get 0 volts at the detector test point.) It still isn't evident that this is caused by electrical problem in circuitry. I decided to try experimentally the following - Connect A2TP13 (A15TP6) to scope Set frequency to 15.55 MHz (same as setting to 5.55 MHz, but didn't want to concern "out of range") Set A19R3 (pretune) fully clockwise Adjust A19R9 (detector) to see 50% duty cycle on scope If A19R9 cannot reach 50% duty cycle (likely), adjust A19R3 slightly counter clockwise and repeat previous step From this point Watching scope, adjust frequency down towards 10.000 MHz, watching to see if duty cycle stays at least 20% from (0% or 100%) limit Watching scope, adjust frequency up towards 19.999 MHz, watching to see if duty cycle stays at least 20% from (0% or 100%) limit If either of the above exceeds limit (duty cycle gets close or to 0% or 100%), adjust A19R3 slightly counter clockwise, return to 15.55 MHz, adjust A19R9 back to 50% duty cycle, and repeat the previous 2 steps. This may (well) be masking a problem I can't yet find, but seeing as at worst I get to try repair again, I'm going to put the unit back into it's (occasional) service. (I do wish PLL unlock conditions were made visible without disassembly, but at least I know now to keep eye on frequency counter if anything is suspect...) Thanks for everyone's suggestions and patience! Dave |
Re: Manual for HP 466A amplifier
John, if you’ll share your email address?with me, I’ll send the schematic.? Jeremy? N6WFO? On Sun, Mar 2, 2025 at 8:25?AM John Griessen via <john=[email protected]> wrote: On 3/1/25 08:45, Jeremy Nichols via wrote: |
Re: Manual for HP 466A amplifier
Good point. I’d rather patronize Artek and save us both time and money.? Jeremy? N6WFO On Sun, Mar 2, 2025 at 8:37?AM Dave McGuire via <mcguire=[email protected]> wrote: On 3/1/25 23:06, Jeremy Nichols via wrote: |
3708A Noise and Interference Test Set - Looking for a Service Manual
Hi,
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I just pulled my 3708A off the shelf for a bit of a spit polish ready to sell it off and I'm looking for a service manual for the performance test and calibration procedures.
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I can't seem to find anything but the Operating Manual in the usual places.
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Does anyone have a digital copy of the service manual for this instrument?
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Thanks!
Jared |
Re: HP Agilent 8753ES VNA repair [Help]
开云体育Hi, ? Starting point VCXO are correct frequency with 40.000MHz. At TP20 you have a frequency of 39.100MHz, and at the output of divider 40 you get 977.5kHz. This indicates, that the divider by 40 is correct but the frequency is wrong from VCO. ? At output of mixer 40MHZ from VCXO is mixed with 39.100 MHz (>16 MHz?) to have around 900kHz (909kHz). At output of mixer 40MHZ from VCXO is mixed with 39.280 MHz (< 16 MHz) you will have around 720kHz. Mixer is OK, but bad frequency from VCO, and good frequency from VCXO. ? Phase detector received bad feedback frequency from VCO (example for HIGH band, 909kHz instead 160kHz)… The PLL is open loop for a reason unknown at this time. ? Correction: TP6 is a TP from output mixer (H160kHz, L=4kHz), and TP7 is the reference for PLL (40MHz from VCXO divided by 250 for HIGH BAND and divided by 10,000 to have 4kHz). ? First question: Is the reference coming from the VCXO divided to have 160kHz for the high band and 4kHz for the low band correct at TP7? The VCO is functional, but the frequencies are incorrect, can the VCO range cover the expected frequency band, between 39.84 and 39.996 MHz. The electrical schematic shows the PLL section of an 8753D, which should be quite similar if not identical for the 8753ES. A way to test the VCO range should be found…remove serial resistor near the TP to inject DC voltage. But this verification can wait, and the verification of the phase detector and especially the integrator are the next points. ? I must go, come back later today. ? De?: [email protected] <[email protected]> De la part de MattSNE via groups.io ? Hello Yves, ? Thank you for your last post.? ? My VCO frequencies in TP20 are not correct. I have : - a RF signal is at 39.100 MHz, -1.3 dBm instead of 39.840 on your board for frequency >16 MHz? - a RF signal is at 39.280 MHz, -1.3 dBm ?for frequency <16 MHz? ? The 2sd LO is at 977 instead of 996 this is why my sampler FI output is at 23 MHz instead of 4 KHz. ? My VCXO is at 40.000 precisely. The VCO output to the mixer do not correctly converts the signal to L=4kHz and H=160kHz from what I measure. I have a signal at 909 KHz here. _ ? ? ? ? ? On PIN 2 on the divider output : 39.100 MHz divide by 40 : 977 KHz. -> The 2sd LO frequency I measure. ? ? ? ._,_._,_ 开云体育 Links: You receive all messages sent to this group. View/Reply Online (#150591) | Reply to Group | Reply to Sender | Mute This Topic | New Topic _._,_._,_ |
Re: Service manual scan post processing
On Sun, 2 Mar 2025 at 16:25, Bert via <el_bert0=[email protected]> wrote:
A very useful amount of cleanup can be done simply by comparing each pixel on its own to the average of the wide neighbourhood pixels. That works equally well for text and schematics, since it has no concept of either and they are both high contrast. It does not work well with photos. How well such text/schematic cleanup works depends on the original's quality. Unsurprisingly, higher XY resolution and uniform illumination/background are advantageous, since both allow the "slicing level" to be more easily determined and more uniformly applicable. Provided there are sufficient pixels for the text characters to be reasonably well formed (open loops, no "spurs"), OCR is then possible. Evidence: a couple of manuals I have quickly scanned on an ordinary printer/scanner/copier, post processed into TIFFs inside a PDF file, and somebody else has OCRed. I have no comment about vectorising; I have never had any use for such a tool. I would expect it to be as (un)successful as decompiling binary object code back into a high level language source code. |
Re: Service manual scan post processing
On 3/2/25 11:25, Bert via groups.io wrote:
While we seem to all agree that JPEG compression is not ideal, there ARE lossless options for TIFF and thus PDF formats.At the museum, we use ITU-T T.6 (Group 4 FAX), which is lossless and very effective. -Dave -- Dave McGuire, AK4HZ New Kensington, PA |