Search results

  1. nabeelsayegh

    Luxman M4000a Power Amplifier Help

    Bump... Please...I am desperate here. Anyone have one of these that could help me out? At this point, I'd be willing to buy a fully working m4000a if it means I can have a reference unit to fix the one I got here.
  2. nabeelsayegh

    Sansui AU-7700 motorboating at max treble setting

    Great thread on this topic. I am actually having the same problem. full system recap (except for main filters), replacement of small signal transistors with KSA992/KSC1845. pots and switched scrubbed very well. I replaced C903 (the 3.3uf/50V mylar cap) with a Panasonic polyester equivalent...
  3. nabeelsayegh

    Project One Mark 1500 documentation

    Unfortunately, I never got one. I had to settle for some 'educated' guesses.
  4. nabeelsayegh

    Luxman M4000a Power Amplifier Help

    Wanted to circle back on this to see if anyone has an M4000a amplifier that would be willing to help me out with getting some reference photos from your unit. I am willing to compensate you for your time. I need to get this repair done asap and due to the absolute lack of information available...
  5. nabeelsayegh

    Hartke LH500 no bias

    So, I just saw something that caught me off guard. On the schematic for this amplifier board, there is a notation in two spots that say "open for LH1000". Based on where these are at, I just realized that these are jumpers on the circuit board. Well, If these are supposed to be open for an...
  6. nabeelsayegh

    Hartke LH500 no bias

    Interesting. So i ended up lifting the two diodes you mentioned to see what would happen and before i could test the result, the bias pot started to smoke. I'm going to have to put them back in place and re-test this again. I appears i had some excessive current going through that pot to get...
  7. nabeelsayegh

    Hartke LH500 no bias

    I had pulled all 8 of the output transistors and checked them independently and they are all testing good. Did a diode test on them and clamped them into a transistor tester. gains all seemed to match. Same was true for the driver pair. Do you think that the two transistors i replaced (to...
  8. nabeelsayegh

    Hartke LH500 no bias

    Voltage across R314 i am measuring about 1.6V. Q308's BE voltage is 0.6V. Re-measured the EC voltage and it is about 2.2V.
  9. nabeelsayegh

    Hartke LH500 no bias

    Sorry, was out of town for a while and just got back to the shop. Going to take another look at this now and see what I can find.
  10. nabeelsayegh

    Hartke LH500 no bias

    No takers?
  11. nabeelsayegh

    Hartke LH500 no bias

    One other thing of note....Transistor pairs Q306/307 and Q304/305 seem to be getting pretty hot. Not sure if this is 'normal' or not, but mentioning it nonetheless.
  12. nabeelsayegh

    Hartke LH500 no bias

    Hoping someone can help me out with this amp. This came in due to what appears to be a common problem with the differential 2SC3200 transistors causing high DC voltage at the outputs which in turn puts the amp intermittently in protection mode. Based on my research, I had installed a pair of...
  13. nabeelsayegh

    Tascam/Teac 112 FF/RW problem

    I pulled this unit back onto the bench after tabling it for almost a year. I am still having the same issues and could really use some help. At the very least, can someone confirm that it is not "normal" for this desk to only running for a few seconds in FF/RW. I assume no...but i feel like i...
  14. nabeelsayegh

    Verification on appropriate MOSFET replacement for P14NF12FP

    Hello. I am working on a DAS Action 15A power amplifier and apparently it has these amp modules (3 of them) that plug into a main board. One module powers the Compression horn and the other two run in parallel and power the woofer. I have identified one bad module and it has a pair of these...
  15. nabeelsayegh

    Luxman M4000a Power Amplifier Help

    Absolutely! You are an absolute life saver. I am actually going to be out of town this coming week so this will be good timing. The nice thing about this unit is that it is modular.....except for the front panel...which is where i think i am going to need some photos of. I may also need to...
  16. nabeelsayegh

    Luxman M4000a Power Amplifier Help

    Bump... Really could use some help front anyone that has a M4000a. I am just looking for some reference photos of the boards i mentioned above.
  17. nabeelsayegh

    Luxman M4000a Power Amplifier Help

    Some pictures of the traces in question
  18. nabeelsayegh

    Luxman M4000a Power Amplifier Help

    Hey everyone....i am in need of some urgent help. I have been working on restoring one of these beasts for a customer. All went fine but i was getting to the end of the job and had to deal with one final issue (that it came in with.) The issue was that the LED meters were not working. The...
  19. nabeelsayegh

    Parasound HCA-2003A bias

    Tell me about it. I would have just replaced them if I had the same ones in stock. But these were some heavy duty ones with odd pin configurations. Once i pulled them apart, oh man, all the contacts were completely black and loaded with carbon build up. It took some effort to carefully clean...
  20. nabeelsayegh

    Alternatives to MJ21192/93/94/95 transistors

    So its no surprise these are murder to find and the big boys are always on backorder. The timelines seem very ridiculous; in some cases, up to a year to get them. Forgive me if this was already discussed somewhere, but are there alternatives to these that are readily available?
  21. nabeelsayegh

    Parasound HCA-2003A bias

    I ran it at 20mV and it got reasonably warm...not much warmer than when i had it at 15mV. I did actually find out that the problem I had was not actually bias voltage related. The issue I was having was dirty relays causing intermittent contact at low output volume. This is a common problem...
  22. nabeelsayegh

    Parasound HCA-2003A bias

    Good evening.... I just finished repairing one of these beasts and I have a question for the masses. I could not find a service manual per se...only a schematic for an HCA-2003. (Not sure if the 2003A is any different, but comparing the unit to the schematic I had, it seemed to be the same.)...
  23. nabeelsayegh

    Sherwood SEL-200 Transistors - Help Please!

    By the way, all the replacement transistors noted above all seem to be working just fine including the use of the MJ21196 in place of the original RCA S200's.
  24. nabeelsayegh

    Sherwood SEL-200 Transistors - Help Please!

    Here's a few more....
  25. nabeelsayegh

    Sherwood SEL-200 Transistors - Help Please!

    Here are some pics of the unit up close and personal. Note: I am going to come up with a 3D printed mount for the new main filter cap.....dont worry...i am not planning to leave it zip tied in place.....even though I did actually think about it....LOL.
Back
Top Bottom