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  1. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    I got my mouser order and replaced all of the electrolytic caps on the front meter board. The intermittent output issue is now gone, but one of the meters has stopped moving with the input. I swapped the 4558s to the opposite channels and the problem moved with the op-amp, so I have ordered some...
  2. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    Thanks a lot. This is an incredibly generous offer. I will PM you so we can chat about the details.
  3. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    You seem to have made some assumptions about what is going on here... I never said I was just going to get it going and then run it hard day in and day out as if it were brand new. I simply said I wanted to diagnose and repair the amp before I put new output devices in. Yes they are old, and...
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    Phase Linear Dual 500 Diagnosis Assistance Requested

    Why would I shotgun an amp with a whole bunch of new parts without testing and fixing the problems first? I don't have a bunch of money to throw at this thing and it's already going to be better than anything I own and/or can afford to get into, so I'll take my time with it and replace what...
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    Phase Linear Dual 500 Diagnosis Assistance Requested

    I would need 2 tp9054 transistors to keep things in line with what is in the amp. I do believe I am going to keep what is currently in the amp and buy some replacements while I get it in order. I will upgrade it once I get it sorted out and running right.
  6. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    I see they are about half of that on Ebay (even from US sellers) but I really don't trust ebay sellers, as I have heard there are a lot of fake parts out there. What are the reputable sources for these devices other than something like Mouser or Digikey?
  7. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    Thanks for the confirmation that the parts are the same, Laatcch55. It looks like I can get the transistors from Mouser for about 7 bucks a piece, so about 200 bucks for both channels.
  8. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    Based on what the manual states, shouldn't I replace all of them if I move to a new part number? I had just planned on replacing the bad ones...
  9. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    I got a few more hours in with the amp on the bench this evening and I think I have found the cause of the amp not switching to Low Z mode. The LED indicator for the Low Z mode seems to be integral to that circuit functioning, and it currently doesn't read on my multi-meter in either direction...
  10. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    Thanks again Ed. I am actually running through the amp now, testing at all of the transistors. I was hoping that all of the issues were focused to the driver board at the back of the amp, but it seems with the High Z/Low Z switch not working, the face plate needs to be removed and I need to...
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    Phase Linear Dual 500 Diagnosis Assistance Requested

    I have noticed something else about the amp. It seems to be stuck in High Z mode, and the selector switch on the front panel does not make a difference when changed. I have ordered a full service manual for the amp, as the stuff I have found online has been very sparse and incomplete. Hopefully...
  12. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    Thanks a lot for the suggestion Grapplesaw. I will take a look at the jacks and see if they are loose. Thanks.
  13. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    Thanks a lot for all of the information Ed. It was a pleasure talking to you as well. I did a little more experimentation, and while the outputs on Channel B are working, something on the driver board is not right, and the audio comes in and out when passing signal. The meters never stop or...
  14. Z

    Phase Linear Dual 500 Diagnosis Assistance Requested

    I have recently acquired a Phase Linear Dual 500 Series 2 amplifier, and am in need of some assistance in diagnosing a potentially dead channel. Upon receiving the amp, it was missing the mains fuse, along with the fuses for channel A. The channel B fuses were present, but blown. I popped the...
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