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  1. Enginuitor

    Help with power supply repair

    After some meter/scope work, I have determined that the oscillator network for the '3524 is operational, as pin 3 (osc/sync) is generating 3.5V pulses at about 30kHz as specified by the datasheet; however there is no signal from the outputs! I am now going to start backtracing from the regulator...
  2. Enginuitor

    Help with power supply repair

    By the way, the "chip in charge" here is an SG3524. The only other IC on the board is a photodarlington optocoupler, which appears to activate the shutdown relay. I'm going to probe around the '3524 with my oscilloscope and see if I can find any signs of malfunction.
  3. Enginuitor

    Help with power supply repair

    In addition to the power output terminals, there is a screw terminal block on the back with the following terminals from left to right: A1, A2, A3, A4, -S, -, +, +S, A5, A6, A7. -S is jumpered to -, and +S is jumpered to +. Originally there were also a few more jumpers near A1-A4, but being the...
  4. Enginuitor

    Help with power supply repair

    The other day I stopped by Halted Specialties Company in Santa Rosa (an electronics surplus place) and managed to talk them down to $25 for a large 0-40VDC @ 0-10A lab supply. It's by "Power Ten Inc." and the model number is 3101-4010. It's a big rackmount chassis with a pretty basic design...
  5. Enginuitor

    PSU repair, found strange cap, need guidance

    I don't think this cap is the problem. Interestingly, I removed the SG3524 chip (which controls the voltage and current regulation) and the unit operated exactly the same as it had before! Time to replace the chip, methinks?
  6. Enginuitor

    PSU repair, found strange cap, need guidance

    Tore off some of the heat shrink and tested between the leads and the can. None of the leads have continuity to the can. I stand with my position that this is a single cap.
  7. Enginuitor

    PSU repair, found strange cap, need guidance

    It's possible it had something to to with the component density and the fact that this is a single-layer hand-routed board (before the days when computers figured it out for you!). From the way the traces are laid out, perhaps they just thought it would be convenient. I am pretty convinced that...
  8. Enginuitor

    PSU repair, found strange cap, need guidance

    I have confirmed perfect continuity between the two sides, on both leads, with both the multimeter and the "lightbulb" test. Can I reasonably expect that this is a BAD thing, and possibly the cause of my problems?
  9. Enginuitor

    PSU repair, found strange cap, need guidance

    And here's the whole thing...
  10. Enginuitor

    PSU repair, found strange cap, need guidance

    Here we are! This is the capacitor...
  11. Enginuitor

    PSU repair, found strange cap, need guidance

    I'm afraid not. However, if I feel up to it I might draw one out. It would probably take most of the day, but could help a lot with the debugging process. I'll try...
  12. Enginuitor

    PSU repair, found strange cap, need guidance

    All four leads go different places. However, because this is an old-fashioned single-sided board (hand-routed traces, etc.), it is possible that they just used this particular capacitor instead of the two-lead variety because it doubled as a convenient set of high-power jumpers. I will take the...
  13. Enginuitor

    PSU repair, found strange cap, need guidance

    I recently stopped by HSC (a local surplus place) and found a big old lab power supply that came from the Lockheed Martin labs in Sacramento. Standard 4-knob controls (coarse/fine on both voltage and current), analog meters. 0-40 VDC @ 0-10 amps! Only problem was, it didn't work. So I managed to...
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