| Electronics > Repair |
| Advantest R3132 Spectrum Analyzer repair information |
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| Gianni:
I revive this topic that I found very useful for me, hoping that someone is still there to give me some help. I got for free an Advantest R3132 with TG. Replaced the battery, it "seems" to work but really doesn't, because the trace (and the TG) is shifted about 20MHz toward left and the signal is 5dBm lower than real and noisy. The frequency is not stable and the trace drifts slowly toward left. The manual self-test (SHIFT/1) says that RF does not pass. I already read the documents above and I am going to do the first test, but I would like to have some help. I am not definitely a RF expert. I understand that I must do what it follows: • remove the RF group from the housing (done); • remove the lid from the RF group, paying attention to the rubber details that risk to fall when you re-move the lid itself (done); • place the RF group on the table, with no connection (done); • identify the LO power supply point and solder a small piece of wire to it (identified - see the arrow in the photo - is that point OK?); • identify a ground point and solder a small piece of wire to it; • determine the power supply voltage; in my case, there is not the big 39 ohm resistor, so I need to give 6V power supply, not 11; • connect a suitable 50 ohm spectrum analyzer to the 2nd Local Oscillator monitoring port; I didn’t have such SA, so I am going to use a RACAL DANA 2101 frequency meter (up to 22 GHz) - what do you think?; • give power supply (6V); and then proceed as described in the above documents. Did I understand correctly? Then I have other questions about the VCO centering, but perhaps it is better to proceed by steps. Thanks for any help… |
| Fraser:
All sounds right to me. I have used a frequency counter to setup the VCO dielectric trimmer but that adjustment is tricky at the best of times. The amplitude of the oscillators output varies greatly whilst trying to set the centre frequency. This is why another spectrum Analyzer makes the job a lot easier. With an SA you can choose the best location of the trimmer for both correct frequency and highest output amplitude. Be warned, these VCO’s can be so far out of tune due to ageing that the only way to get the correct centre frequency is to remove the dielectric trimmer arm completely and then adding small pieces of copper foil to the PCB traces where the arm used to sweep. I have seen SMD 0 Ohm ‘resistors’ used in place of copper foil so they may be easier to try. Size 0603 and 0804 are suitable sizes of zero ohm ‘resistor’. If you are very lucky just removing the dielectric trimmer arm will bring the VCO close enough to the desired frequency and no soldering of SMD ‘trimming’ resistors will be required. Fraser |
| Gianni:
Wow, thanks for replying, it's an honor to talk with you! In the meantime, following your documents, I could fix the SA and the TG. I could not check the VCO behavior because my R3132 is of an older type, and there is not the passage for the "blue wire", but just an internal test point. In the photos you can see what I did. In the case of the TG, there is also a small fragment of wire in the bubble of tin. Now everything seems to work rather well: both the SA and the TG passes the tests and the self-calibrations and appear to be precise. My R3132 has in addition the "high stability oscillator" option n.20. A nice instrument. Thank you very much for your work, without it I could use my R3132 just as door stop. Gianni from Florence, Italy |
| Gianni:
Hi, here you can find a document that resumes my experience: http://www.k100.biz/zParade/Advantest_R3132.pdf It will be a chapter in the HP book, here you can find the latest draft: http://www.k100.biz/zParade/HP_book_draft_9sep.pdf |
| KE5FX:
--- Quote from: Gianni on September 09, 2023, 06:55:36 pm ---Hi, here you can find a document that resumes my experience: http://www.k100.biz/zParade/Advantest_R3132.pdf It will be a chapter in the HP book, here you can find the latest draft: http://www.k100.biz/zParade/HP_book_draft_9sep.pdf --- End quote --- Great to see you're doing coffee-table books for HP and Advantest. :) Looking good! (OT, but while you're working on those 8640Bs, consider adding a small light bulb or two just above the clear plastic meter housing before you close them back up. When you see how good the illuminated scale looks, you'll wonder why HP didn't do that themselves.) |
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