transistor

  1. J

    Marantz 2215B Power Supply Transistor Subs

    Hi all, I am currently restoring a Marantz 2215b as my first restoration. I am working on the power amp and I am having trouble sourcing a suitable replacement transistor for H709 and H710. The originals were 2SA684 which folks have said to substitute with KSA1220AY. However KSA1220AY is out of...
  2. R

    SAE MARK XXXIB distorted channel, then loud buzzing.

    Hey what's going on? so when I play music through the amp the left channel is distorted the right channel is clear. when I moved the amp, both channels went completely distorted and I had to unplug it, loud buzzing through the speakers and buzzing around the bad darlington area. I pulled the...
  3. M

    Pioneer SX770 left channel preamp out hiss

    My SX770 has a hissing noise only heard on the preamp RCA out on the left channel. It is the same volume regardless of how loud the volume is turned, and is present regardless of which input is selected. Any idea which transistor may be the culprit? Everything else works perfectly.
  4. C

    Onkyo TX-4500 Transistor replacement

    Hi Folks, I just joined as I have a question about what modern equivalent to use in replacing a 2SC945 in my Onkyo TX-4500 (not MKII). This is for Q504 and the parts list in the service manual lists it as 2SC945(L, P). I have both the KSC1845FTA and KSC945CYTA on hand. My question: is one or...
  5. david winter

    Denon PMA-701 : 2SC1735 & 2SC1775 subs

    Hello, I'm going through a nice Denon PMA-701 amp. Seems a bit cheap in manufacture, but worth restoring. The tone control uses a number of 2SC1775 and 2SC1000. Haven't replaced any yet. The output stage also has a pair of 2SC1775 which I plan to replace by 2SC1845 unless there is a better...
  6. OFrank

    Marantz 2325 Transistor Substitutions.

    Hello Everyone, I need some help from all the Marantz guru’s. I have read in another post that the possible cause to an intermittent loud popping in the 2325 power amp might be the H706 - 2SA818 and H707 - 2SC1628 transistors. I see that the recommended replacement transistors are KSA1381for...
  7. Douk

    Rotel RB-2000 main transistors

    Hi! I am restoring a Rotel RB-2000 power amp by replacing all electrolytic capacitors. There is only on e question I have with regards the unit I am working on. I am not sure if the main transistors are original and I would like to restore it to its Original glory. What main transistors are...
  8. R

    Sansui BA-3000 No Power

    Greetings everyone, I have a Sansui BA-3000 I bought with issues. I tested it and realized that the RL02 relay was not functioning and decided to replace both relays on the (F-2511) protection board. I then realized the cermet resistors (R01 and R02) were burned up. I replaced them and the new...
  9. C

    Magnavox Astrosonic R222 Chassis

    Hi all, I recently acquired a Magnavox Astrosonic 1P3661 (chassis R22276 DE) from its original owner. It’s in great condition and is solid state. I was able to restore the W821 turntable with a tear down, relube, new stylus, and new idler wheel. I’m now focusing on the chassis. Overall sounds...
  10. badwithnames

    Another Identifying Transistor Help Thread

    Hello all, I'll be doing a few restorations (SX-950, SX-880, SA-8800) in the near future and have been doing a lot of learning here on the AK forums. I've got a decent parts list going for all my projects but am having issues when it comes to what exactly I need to be replacing for...
  11. AshhBoy_

    dbx cx3-mkI faulty channel repair

    After having my cx3 fixed because of a dead right channel on arrival, I used it daily for about two years with mostly no issues. Two days ago, I fired it up to discover my right channel was presenting a large ac-synced humming noise. I quickly unplugged everything and checked all my wiring, to...
  12. D

    Transistor replacement pioneer sx-3600

    I have a pioneer sx-3600 with a bad output transistor 2SD883A with the bat wings (xm20). I cant seem to find a replacement for it. I've checked with the local seller in my town and he couldent even find a suitable replacement and hes been doing it since the 70's. I've checked digikey & mouser...
  13. D

    Spec-2 Troubleshooting Output Transistors

    Looking for advice on determining if the output transistors are leading to a channel appearing to be out. What I've determined is that I have the correct voltage at 15,16,21,22, but do not see any voltage at the output legs of the transistors. I have taken each output transistor out and did a...
  14. Impact

    Realistic STA78 Resistor/Transistor fun

    Looks like il be adding to the fun as I am as well a STA78 owner that has crackling/popping out of only the left channel. After searching the forums, I put together that this is likely a bad transistor and decided to start doing a cold test of the transistors using super cold spray. During...
  15. T

    nad c326bee integrated amplifier with defective pre amp circuit help?

    According to the previous owner it was working but suddenly they could hear pops from time to time via the speakers until one day there was a very loud pop and it stopped functioning properly. I tested it and it seems like the problem is limited to the pre amp as the power amp is working fine if...
  16. K

    Marantz 1090 Power Amp Transistor Replacement

    Hello, all. I have a 1090 on the bench that had a failure in the power amp driver board. It appears Q718 shorted from the base to the emitter. The transistors in the path current flowed all seem to be effected, though Q718 is the only one with a dead short. I'm going to replace all the effected...
  17. Racingh11

    TO3 MOSFET - end of life

    I just went to get some new TO3 output transistors from ProFusion / Exicon, and they are now marked as 'end-of-life'. Better get them while they last. Does anyone know of any other TO3 lateral MOSFET transistors out there that are made by reputable companies...
  18. James Cox

    Sherwood s-7900 with a dead right channel

    So I picked up a Sherwood s-7900 in beautiful cosmetic condition. Actually I picked up an entire carload of gear and after getting a pioneer sx-3700 and sx-780 sorted out(for the most part, still waiting on some final parts to fix a problem with the phono stage) and ordering some parts for the 2...
  19. J

    DISTORTION BOTH CHANNELS NAD MODEL 200

    First of all I wanted to thank the work done by all the members of the website, it really is very helpful for people like me who are just starting out in this world. I hope someone can help me with my model 200 NAD amplifier. The amplifier has distortion in the two channels, I changed 3...
  20. Mrcoolest123

    Pioneer Transistor replacement

    hello! I just got a new piece of gear for my collection, a pioneer sa-710. Got for a nice price because the seller told me it didn't work and wasn't able to repair it. I have some knowledge on electronics so I took it as my project to repair it. I already found the replacements for the burn...
  21. Mat86

    Replacing a power transistor?

    So I'm trying to restore a Pioneer RG-2 processor, despite being a novice, and picked up a broken unit. Fiddling around inside I found a power transistor to be rather loose, and applying pressure would bring the unit back to life. The part is Q32 in the service manual, appears to be a...
  22. EnzoFerenzo

    marantz 2238b power main board transistor

    I am looking for a suitable replacement for the thermally coupled transistors, in particular Q708, part number listed in the manual is:HT315672BO. I've looked online, and it seems like an old, obsolete part. Any help getting a substitute is appreciated. I've included below part of another thread...
  23. grandpaslab

    Rotel RX-803 - 2SA912 sub?

    I'm trying to eliminate the last few gremlins in this Rotel. It crackles a bit and I've read that KSA912 gets noisy (and hot) so I'd like to replace Q605 and Q606 on the main amp board, which are listed as "main amp bias compensator". KSA1013 seems to be the go-to sub, but I don't have any on...
  24. R

    Sansui driver transistor alternative

    Friends, I wonder if I can ask for some help. I'm repairing a Sansui 310. Have replaced blown power transistors (2SC1061 replaced with MJE15034G). There was also a blown driver transistor - one of two 2SA678s (TR 807 & 808) - which I replaced with some 2SA1015Ys, noting the different pinout...
  25. VonKuhn

    Kenwood KR-7600 transistor problems

    Hello, after weeks of searching I am finally desperate enough to post a question and look for help. Recently I got a Kenwood kr-7600 in great condition to repair, just a bit dusty, and no sound at all. After some searching, I found a transistor (2SC1419 NPN) surrounded by dark spots on the board...
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