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  1. S

    Sx-680 Both Channels Distortion

    Ok found the culprit R347 100ohm was out of spec. It’s hiding just next to the filter capacitors and hard to see it.
  2. S

    Sx-680 Both Channels Distortion

    Reflowed most of the solders Made sure the ground screws are tight Sometimes the sound totally disappears and only when cranking the volume up it comes back yet very distorted. I’m confused what to do next
  3. S

    Sx-680 Both Channels Distortion

    Q402 gives 54v on all leads really Took it out and it was shorted Replaced with KSC2690AYS Voltage is E52 C54 B52 Sound still distorted just when I thought this was over :( I even replaced filter capacitors
  4. S

    Sx-680 Both Channels Distortion

    D309 cathode 13.7 anode 7.8
  5. S

    Sx-680 Both Channels Distortion

    Sorry I measured R402 by mistake. Someone mounted R410 under the pcb. R410 is reading -38.4 Balance both sides look very clean waves Q506 E 2.3v / C 8.3v / B 2.9v Q505 E 2.4v / C 7.3 / B 3.3V Wave looks very clean on the collectors of these transistors And looks very clean on both sides of C301&C302
  6. S

    Sx-680 Both Channels Distortion

    R410 is giving +34vdc at one side and +38vdc at the other
  7. S

    Sx-680 Both Channels Distortion

    It doesn’t flicker anymore The last I noticed before it started distorting was the lights flickering Unswitched = 233Vac Switched = 233Vac Main filters : C413 = 37.4Vdc C414 = -37.8Vdc Pins 2&9 at the stk’s have the same voltages as above.
  8. S

    Sx-680 Both Channels Distortion

    Cleaned and reflowed all fuse holders Replaced the fuses with new made sure the grounds are tight and reflowed them Tried with another STK No change All capacitors on supply board were changed but not the filter caps This is the image I get it the scope
  9. S

    Sx-680 Both Channels Distortion

    Power supply?
  10. S

    Sx-680 Both Channels Distortion

    Yes sure You suggest they are faulty? Both the same time failed maybe I can take them out and check them What’s the way to confirm they are ok or not
  11. S

    Sx-680 Both Channels Distortion

    Yes for 2 weeks everyday use
  12. S

    Sx-680 Both Channels Distortion

    Lights were flickering a bit before it made what I was describing All caps new except the filter caps.
  13. S

    Sx-680 Both Channels Distortion

    No excess voltage in the speaker terminals. After a test the problem is in the power amp If anyone can help what to check would be much appreciated.
  14. S

    Sansui 5050 get very hot

    Still trying to solve this and I really need your help All pins at the supply board match EXCEPT the -Ve on the right channel. Checking C607 I get 0v at it Checking D605
  15. S

    Sansui 5050 get very hot

    You are forgiven :bigok: as long as you help me out with this 5050 like you did with the 881 :)
  16. S

    Sansui 5050 get very hot

    driver board disconnected. Unit takes 10 seconds to get out of protection. The board code is F-2701 which is different from the service manual Took pin #21 and no change
  17. S

    Sansui 881 stays in protection

    Man you are a genius Replaced C11 with new 100v/100uf cap. It got out of protection. So many thanks I really appreciate your patience and workthrough with me
  18. S

    Sansui 881 stays in protection

    F02 - 21.6 VAC. D01 - cathode 13.3vdc anode 0vdc
  19. S

    Sansui 881 stays in protection

    D06 Cathode : 11v Anode : 7.8v Checked again the voltages of TR04/05 TR04 B : 0.68v C : 7.6v E : 0.056v TR05 B : 0v C : 0.68v E : 0.056v About orientation - I think they are oriented ok According to my Atlas transistor tester But this datasheet says different...
  20. S

    Sansui 881 stays in protection

    Hi Thé transistors are on Power Supply Board F-2437. I checked - they give me me the following : TR04 B 0v C 0.6v E 0v TR05 B 0.6v C 7.3v E 0v i took the measurements of the relat from underneath the pcb. The pins that gave me the voltages at the relay are the closest ones to the above transistors
  21. S

    Sansui 881 stays in protection

    I started suspecting that maybe the relay is faulty But I measured voltages and there is 0 volts at all pins except 11.3V & 7.8V at the inputs
  22. S

    Sansui 881 stays in protection

    Héllo The receiver stays in protection. Pulled out the driver board (F-2436) - stays in protection. Took each output (2sc1115) out and tested - stays in protection. All fuses are ok. Measured voltages at TR01/TR03 & TR02 they all as specs in schematic. Would love your advise and help what could...
  23. S

    Sansui 5050 get very hot

    emmm the TR09/TR10 are on the driver board My problem is at the supply main board. disconnected PIN 22 (right channel) - no change. by the way which schematics are you looking at ? Thanks Hyperion
  24. S

    Sansui 5050 get very hot

    I think it’s TR601/TR602...
  25. S

    Sansui 5050 get very hot

    Replaced the fuse holders and now fuses don’t glow. Right channel outputs transistors get hot. All outputs were tested out of the heatsinks and test good. Compared voltages left (good sounding channel) and right channel pins on board F-2701 : All pins match except the second to last (pin 9) Left...
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