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transistors

  1. HiFi Poland

    Chinese counterfeit/knock-off power transistors

    Hello, I’m starting this thread because I wanted to describe an interesting issue concerning transistors. These are my own experiences, and I thought they might be useful to someone. I mainly restore turntables, but from time to time I also repair or restore an amplifier, mostly for myself or...
  2. larryleezard

    So how bad is the bad transistor list really... shoot on sight or more check here first if trouble shooting?

    I am refurbishing an SA-8500ii and love it. My gosh I really like this amp. I am just finishing up with the amp boards and looking at the sca798 double transistors that are currently working and wondering if I should swap them out for some matched A992's or let them ride? Thoughts? Insights...
  3. F

    Substitutes for uPA74 uPA75 double transistors

    I recently acquired a Japanese amplifier with a dead channel. I tracked down the fault to a dual transistor uPA75. The base–collector junction is shorted, which in turn burned the R7 resistor. None of the other components seem to be affected. I am looking for a good substitute for this dual...
    • fox
    • Thread
    • learning substitutes transistors
    • Replies: 9
    • Forum: Solid State
  4. HotRodStereo

    Audio distortion from Phono Stage

    Hi! I am still learning the dark arts of vintage audio repair, and I am looking for some sage wisdom on a unit I am trying to fix. Here is the story - Its a Sony STR 2800, I cleaned it up and it was working great, got everything all balanced and checked and listened for a while and then sold...
  5. B

    Marantz Model 25 transistor substitutions

    I'm about to re-cap and possibly replace some transistors on a Marantz Model 25. It currently sounds fine, so I don't want to do anything unnecessary, but I'd like to replace any transistors that are known to be problematic. I've checked the Top Ten Worst Transistors list and don't see any of...
  6. E

    Pioneer SA-606 noisy output

    Hello to everyone, I have a problem with my SA-606 (SA-6700 version for Europe): There is an hiss similar to white noise through the headphone output. In the past I did some maintenance: 1) Recapping - used Nichicon "audio grade" KA series (light blue sleeve) for everything but main filters...
    • EqualSign
    • Thread
    • amplifier bias hiss noise recap sa-606 sa-6700 transistors
    • Replies: 0
    • Forum: Pioneer Audio
  7. E

    Pioneer SA-606 noisy headphone output

    (moved to Pioneer audio - my bad)
    • EqualSign
    • Thread
    • amplifier bias hiss lamps noise pioneer recap sa-606 sa-6700 transistors
    • Replies: 0
    • Forum: Solid State
  8. Jrockpsycho

    Need help finding transistors

    Hello, I am rebuilding a Dolby cat-22 module and I need some help finding equivalents for the following transistors (same pinout is preferable): BC414LC BC416LC BFR80 BFR40 Thank you
    • Jrockpsycho
    • Thread
    • question transistors
    • Replies: 2
    • Forum: DIY
  9. lopezluna

    Pioneer sx-1010 amplifier board AWH-032-0 Transistors

    Hi everyone. I have a pioneer sx-1010 that I am doing a restoration on. I have already restored all the boards except the amplifier boards awh-032-0. This receiver was all original and made in 1974. The question here is about transistor Q4 supposed to be a 2SB528 and it has a 2SA809. Also Q7...
    • lopezluna
    • Thread
    • amp board transistors pioneer awh-032-0 pioneer sx-1010 transistors
    • Replies: 6
    • Forum: Pioneer Audio
  10. lopezluna

    Kenwood ka-9100 anyone has a list of currently available transistors to use as replacements

    Hi everyone. I have a Kenwood ka-9100 amplifier that I would like to restore. However after reading the restoration threads on this forum and noticing that many of the transistors used as replacements are obsolete and NLA. I am wondering if anyone has recently made a list of replacement...
    • lopezluna
    • Thread
    • currently available transistors for ka-9100 ka-9100 replacement transistors ka-9100 restoration ka-9100 transistors kenwood kenwood ka-9100 kenwood ka-9100 obsolete transistors replacement transistors transistors
    • Replies: 10
    • Forum: Kenwood-Trio/Kensonic-Accuphase
  11. J

    ACCUPHASE E-205 HELP NEEDED

    Hi all, I have just purchased an Accuphase E-205 which apparently has a channel with the output transistors having problems. The other channel seems to have been fixed previously. I would like to know if someone could help me to make it functional. 1. Help me know if the modified channel could...
    • Joan Biel
    • Thread
    • accuphase accuphase e-205 dc offset mos fet transistors
    • Replies: 13
    • Forum: Solid State
  12. Mat86

    2SB655 & 2SD675 transistor replacement?

    I need to replace the Hitachi 2SB655 and 2SD675 transistors on my amp, but not sure if there how to go about it. I see there are 'NSC' 675s on ebay (NJ, not from China) and some worn 655s from a seller in Canada pulled from a donor unit. Would either of these be the way to go? I've also been...
  13. david winter

    Top Crap transistors list and "not-always-crap" types

    Hi, I have been using the "Top Crap" tansistor list for a while, and wanted to know if there's a place on AK where that list is stored. If so, it would be interesting (if not already done) to update it with more classic transistor references which are not as crap as those already in the list...
  14. oldvinyldude

    Transistor vs Capacitor noise

    Hi folks: I just finished a mechanical refurbishment on a Teac A4010S deck. Tape moves fine, pinch roller engages-all good. I tried playing a known good tape, and I get good level, but the sound is distorted. Heads, switches, pots, and audio jacks all clean and noise free. The distortion is...
    • oldvinyldude
    • Thread
    • caps teac a4010s transistors
    • Replies: 3
    • Forum: DIY
  15. C

    Hitachi HA-610 rebuild question

    I have gotten hold of my father's Hitachi HA-610, the receiver I abused when I was a teenager. It is in excellent working condition, but wanted to rebuild it. After cleaning and lubing all the contacts on it, I replaced all of the electrolyric capacitors. I have two questions: 1. The power...
  16. yotatoyota

    Akai GX-4000D right channel is not recording

    Hello. I'm new to this forum. I'm from Eastern Europe and English is not my native language, so I apologize for any mistakes in advance. So I have recently bought a used black Akai GX-4000D tape recorder which, despite its age, is in great condition overall, but unfortunately, the right...
    • yotatoyota
    • Thread
    • 2sc458 2sc945 akai gx 4000d left channel not recording transistors
    • Replies: 7
    • Forum: Tape
  17. Rob Wain

    Pioneer SX-636 - Rebuild and Speakers

    Hi. I've used the great info you Gents/Ladies' post here to start the rebuild on my SX-636 and PL-12D turntable. Like most, this was the kit my Dad had when I was a kid (the turntable was his, the amp is beyond repair so I have a new to me unit from eBay). They both work pretty well, but I...
    • Rob Wain
    • Thread
    • dc current gain differential pairs pioneer sx-636 transistors
    • Replies: 7
    • Forum: DIY
  18. L

    Marantz MA-700 Monoblock Repair Help

    Hi, I've had a lot of MA-700 monoblocks over the years and they always eventually succumb to intermittent popping. This seems to be a common issue. This area of the P701 circuit board tends to get a charred look: Here is the whole board layout: Here is a schematic of the whole circuit...
    • Lee Hester
    • Thread
    • capacitors marantz repair transistors
    • Replies: 3
    • Forum: DIY
  19. PTL-Pioneer

    Denon PRA-1100 & POA-2200

    Hi all Bought first bits of denon there recently, power amp needs work because speaker terminals all smashed up, the plastic is super brittle. Seems like really nice build quality other than those terminals obviously. Ill post more on that when i take a look at it properly. The preamp needed a...
    • PTL-Pioneer
    • Thread
    • distorted help magic smoke recap and restoration transistors
    • Replies: 24
    • Forum: Solid State
  20. zastin17

    Sansui AU-666 Transistor Substitution List F-1159 - AU666

    For the Sansui AU-666, I hope this can help somebody in the future!!!! Driver PCBs and the UFO transistor was a bit of a rabbit hole for me. Also will cover the F-1159 Driver PCB's As an FWI, PAY ATTENTION TO DRIVER BOARD ORIENTATION UNLIKE I DID, THE SECOND YOU INSTALL THEM BACKWARDS and...
  21. zastin17

    Sansui AU-666 Transistor Substitute? F-1231 Driver/Bias PCBs.

    "Title EDIT" Boards are F-1159, Not F-1231 So Transistors are something I have not learned much about. And when the fail on the tip of a hat. I just don't know what to do about it...... Lol. "I'M BLIND!" Anyway, this Sansui Au-666 worked a few years ago. Sounded wonderful! So good infact, I...
  22. Stereoboy70

    Realistic STA 2100D amp layout

    Hello All. Question..... I’m replacing the transistors on both amps in my 2100D. The service manual shows different layouts for the 507 and 508 transistors. The pic of the L amp shows. B C E but the right shows E C B I’m replacing with MJE 15032 and 15033 which are B C E. The actual amp...
  23. Stereoboy70

    2SC828 pinout

    Question, I found 2 different pin outs for an SC 828 transistor. One pin out is ECB. The other is EBC. Which is correct?
  24. P

    Need help repairing Yamaha A-560 amplifier

    Recently I picked up a "fully working" Yamaha A-560 amp for cheap and it has one small problem - it isn't fully working (gasp)... Sound coming from the left channel is distorted. What I've found out is that both output transistors of that channel were not even connected to PCB. After checking...
    • PauliusA
    • Thread
    • amplifier distortion problem transistors yamaha
    • Replies: 8
    • Forum: Yamaha
  25. sean sweeney

    Kenwood KR-6600 restoration etc.

    I have been working on this Kenwood a lot of this week. A friend sold it to me cheap, as it was stuck in protect mode... I kind of listened in on the amp section and heard that there was a lot of noise from bad transistors, in this case it was the 2sa733's as the differential pairs and others...
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