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Re: HP8566B band amplitude response discrepancy - how much indicates a component failure?
开云体育You’ve gone through the YTO loop calibration, right?? If the pretuning controls aren’t right for your replacement YTO, it might end up off-frequency far enough to make certain bands look worse than others.? ? You do NOT want to mess with the YTX calibration process unless you have a lot of time on your hands and a suitable sweeper. ? -- john, KE5FX ? From: [email protected] <[email protected]> On Behalf Of ed breya
Sent: Monday, May 26, 2025 12:57 PM To: [email protected] Subject: [HP-Agilent-Keysight-equipment] HP8566B band amplitude response discrepancy - how much indicates a component failure? ? I'm still looking at this 8566B I just repaired, and pondering what it takes to do more adjustment. Right now it looks like the 2-5.8 GHz band shows over 12.5 dB lower than in the low 0-2.5 GHz band. I'll probably start trying to tweak things to see what's needed to bring it up to par. This is the unit that had a shot YTO - the oscillator Q had B-C shorted, evidenced by the blown collector bias resistor in one of the "RO" spots. With the fresh YTO and the A20 adjustments done, the 0-2.5 GHz band seems to work fine, so I know the frequency controls and 1LO power are sufficient. ? I think the 13 dB or so less in the next band and whatever amounts in the higher ones should be easy to correct with proper adjustments, but I have never done this on any of my 8566s. I'm wondering whether this initial difference is no big deal in the scheme of things, or indicative of some other failure. From a quick look at the adjustment document it looks like it will get quite complicated and tedious, involving alignment of the YTX with the YTO and such, band by band. There's a lot going on in there. I think the main thing next is to assess the condition of the YTX. ? The only comparison I've done so far is in the overlap of the bands around 2.3 GHz. The low band is checked against the 100 MHz -10 dBm cal reference (which I checked with the 436A), then the response is checked at 2.3 GHz ~0 dBm from the HP70331A and then in the 2-5.8 band. The preselector peaking process seems to work through its routine, so the YTX must be doing some tuning at least. ? Anyway, I think it's likely OK and close enough operationally that it's mostly going to be about adjustments, and not some other component failure. I'll find out eventually, but it seems a lot more involved than I had expected. I'm hoping for a fairly low frustration and anxiety level. ? Should I worry? ? Ed |
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HP8566B band amplitude response discrepancy - how much indicates a component failure?
I'm still looking at this 8566B I just repaired, and pondering what it takes to do more adjustment. Right now it looks like the 2-5.8 GHz band shows over 12.5 dB lower than in the low 0-2.5 GHz band. I'll probably start trying to tweak things to see what's needed to bring it up to par. This is the unit that had a shot YTO - the oscillator Q had B-C shorted, evidenced by the blown collector bias resistor in one of the "RO" spots. With the fresh YTO and the A20 adjustments done, the 0-2.5 GHz band seems to work fine, so I know the frequency controls and 1LO power are sufficient.
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I think the 13 dB or so less in the next band and whatever amounts in the higher ones should be easy to correct with proper adjustments, but I have never done this on any of my 8566s. I'm wondering whether this initial difference is no big deal in the scheme of things, or indicative of some other failure. From a quick look at the adjustment document it looks like it will get quite complicated and tedious, involving alignment of the YTX with the YTO and such, band by band. There's a lot going on in there. I think the main thing next is to assess the condition of the YTX.
?
The only comparison I've done so far is in the overlap of the bands around 2.3 GHz. The low band is checked against the 100 MHz -10 dBm cal reference (which I checked with the 436A), then the response is checked at 2.3 GHz ~0 dBm from the HP70331A and then in the 2-5.8 band. The preselector peaking process seems to work through its routine, so the YTX must be doing some tuning at least.
?
Anyway, I think it's likely OK and close enough operationally that it's mostly going to be about adjustments, and not some other component failure. I'll find out eventually, but it seems a lot more involved than I had expected. I'm hoping for a fairly low frustration and anxiety level.
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Should I worry?
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Ed |
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Agilent/Keysight ENA 5071C Receiver Gilbert Cell Mixer 1GC1-4405
I have been fixing some 5071C ENAs.? Many of them have bad receivers.? Upon doing some tests & research, I noted that the Gilbert Cell Mixers were bad.? This is generally on port 1 on roughly 5 of 10 units, probably due to overheating from the units being left on day and night for years.? These mostly have the part number 1GC1-6234.? Some have 1GC1-4234.? But today I opened up a more recent version which has part 1GC1-4405.??
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Replacement parts for any of these are expensive and hard to source.? It appears that 1GC1-4298 is a suitable replacement for the 1GC1-6234 and 1GC1-4234.? What I haven't been able to figure out is if the 4298 can be used to replace the 1GC1-4405.? Is there anyone who can provide any insight on this?? I've contacted Keysight in the past on this unit, but they pretty much just want me to send them the unit so that they can fix it and charge us accordingly.
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cheers- |
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Re: Agilent E8357A Network Analyzer Phase Lock Lost Error
Useful to be sure the clocking of the frac N counter (5 MHz) reference is ok. Does the manual provide logic?
swing levels? Scoping the clock at W4-1 should be sufficient. Then, does the manual provide a guide to a setup?
of the A8 card if the VNA were set for a CW no sweep condition. Opening the loop to investigate the frac N count?
is required and opening the control of the vco's is needed to see if the control voltage from the phase detector(s) makes
sense. You really need detailed information from the manual if you desire to troubleshoot the A8 card to the component level.?
Assuming, you want to do so. I am not aware of the availability of cards for that instrument.? |
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HP 8702D OPT 011 conversion to 6GHz
Hello,
I bought an 8702D which I didn't receive yet and I am doing some research in the meantime for the Test Set compatibility and also OPT 006 for a 6GHz upgrade. From my understanding if I buy the 85047A Test Set I will not be able to use the doubler in the Test Set because it needs a 6GHz source inside the 8702D. Practically the doubler is not used at all for the 8753D/8702D. I don't understand how exactly it will work, when I will use the 6GHz band, it will show that via the LED on the front panel but it will not include the doubler in the RF path? Doubler will be included in the RF path only if the VNA is 8753A/B/C model? So now I am looking to replace the source module and I found different modules but I am not sure which one is compatible. I don't want to buy something that will not be compatible since these are not cheap. - 08753-60146 (08753-69146) this one seems to be a 6GHz source but it is used in 8753E/ES. Seems to use the same YIG and VTC Oscillator but it has some attenuator attached to the assembly. Form factor seems to fit. - 08753-60003 (08753-69003) this one seems to be also a 6GHz source and I found that this was used in 8753A/B/C/D ?! Is this correct? This one has 2 PCBs stacked and there is no attenuator. It has an assembly that seems to contain ALC/LVL modulator, mixer, amplifier, etc. Do you know if there other source assembly part numbers that I can search for and what is the compatibility with the 8702D? As for the Test Set from what I read there are 2 versions of the 85047A, the older model with coaxial switch and the newer one with the solid state switch, newer one has prefix 3033A and the older one has prefix 2729A. Do you know other prefixes for the two versions? Regards, Razvan |
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Agilent/Keysight AWG 33250A /33220A CAL
hello everyone Bonjour a tous...
This fine 80 MhZ AWG (circa 2016) needs a full calibration similar to the 33220A 20 MhZ. Do either of these generators, use a back up battery or NV ram that can lose the calibration Constants over the years? Can calibrate in a few hours? Any tips or experience (on either part number) is appreciated. Bon Soiree jon |
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Re: Agilent E8357A Network Analyzer Phase Lock Lost Error
I suggest you place your counter into the RATIO MODE.? What I am addressing is rule out a faulty divide
by 2 counter.? ?Since this a significantly robust phase lock synthesizer system, makes sense to try to rule
out simple fundamental elements.? |
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Re: Agilent E8357A Network Analyzer Phase Lock Lost Error
开云体育That is pretty bad. An ovenized crystal oscillator should be able to do at least 10^-7. – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ? From: [email protected] <[email protected]> On Behalf Of Johnny10 via groups.io
Sent: Sunday, May 25, 2025 1:04 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] Agilent E8357A Network Analyzer Phase Lock Lost Error ? Actually measuring again with a counter I come up with 10.000447 Not to say my equipment is perfectly accurate. ? |
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Re: Checking an 8402B Calibrator
It might be simpler to put a 100M ohm resistor in series with the high input on the 34401A in the High Z mode. Your 17.8V reading will now be 8.9V well inside the 10V limit for the 10V, 100M ohm impedance range. If required you can calculate the exact division ratio and correct your reading accordingly.
Don Bitters |
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Re: HP8510C "system bus address error", but then it works
开云体育?Marko, The system may have been set up to use two sources and it’s looking for the second source. Try: Instrument State <Recall><More><Factory Preset> Regards, Steve On May 25, 2025, at 2:14?PM, Marko Cebokli via groups.io <s57uuu@...> wrote:
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HP8561E Jittery Display
Hi, I've some HP specans just obtained as BER items from a local space communication site.
The first one I'm looking at is an HP8561E, it powers on OK and the display is bright but the text is jittery and almost unreadable.
I'm guessing "check out the PSU, Paul" is the way to go but does anyone have any insight on this model/fault they might like to share?
I'm also looking for component level schematics etc.
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The other items I have are all HP859x series.
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Any info welcome thanks
Paul
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HP8510C "system bus address error", but then it works
Got my hands on a 50GHz 8510C with test set and source, everything mounted in a mobile rack with a pullout table.
When I switch it on, it says "caution: system bus address error", but them it proceeds to function OK.? Both the test set and source respond to commands. I have checked the addresses, and they are set as specified in the manual, both on the instruments and in the HP-IB setup menu.
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Not much of a problem, since I can use the analyzer, just a bit annoying. Any idea how to fix this?
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Marko Cebokli |
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Re: HP 8902A Measuring Receiver
Hey there Raymond,
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I've done a little futzing with the power supply and the input amp on my 8902, so I'm happy to try and help where I can.
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I think you might get more traction on the group if you describe the problem you have and see who might have ideas about how to address.
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TonyG |
Froggie the Gremlin
