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  1. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Bad news, The destruction trail goes on: Q613,Q619 blown Q617, probably blown Please remove them and check them out of board. After removing the above, check Q605,Q609,Q611,Q615 in board,please note "prob colors". The diodes you have checked are fine. D609 should be near one of the following...
  2. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Iceman, Don't buy them yet. Better wait till we have identified all blown parts and buy all of them together from digi-key . Shipment of all in a single parcel will probably make the total shipping price lower.
  3. dorke

    Working on a vintage fan - whole thing is electrified when plugged in. What am I doing wrong?

    Welcome to EP. The best advise I can give you is to take it to a proper electrician for fixing. This isn't something a person with "big fat 0% experience" shouldn't handle ,it can kill you!!!
  4. dorke

    Amp In Protection Mode

    O.K. that is fine. With C613 out. Please move VR601 to about it's mid position as shown in the pic. Leave R627 lifted leg connected to GND. Install Q605 and Q607 in their location. Measure the voltages on Q603 and Q607.
  5. dorke

    Amp In Protection Mode

    Yes, 0.291V readingin on the 2V range is fine for now. You did trim it ,right? Please measure the DCV, with both probes on resistors legs, of R607 and R627(the lifted leg connected to GND). and voltages on Q603 relative to GND. C613 is faulty,you should get a replacement for it.
  6. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    The problem with these parts is some of them may be obsolete. So their price may be higher then "normal",and could be that suitable "modern" replacements may be needed. Estimated "Normal" upper limit prices : Q631/Q633 1.5$ each. The others should be 0.25$ each Note: it would be better to...
  7. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    About batwings replacements. I did find the 2SA1215-ND and 2SC2921-ND both from Sanken, they are the same case style. If you buy them from digi-key you will not get fakes,it will be more expansive,but worth it though. http://www.digikey.com/product-search/en?keywords=2SA1215...
  8. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Yes, A chain of destruction that probably started with the breakdown of the batwings and penetrated inwards. You need to take out Q621,Q623,Q625,Q627,Q629,Q631,Q633,Q635,Q637 After that please measure, in board, Q613,Q615,Q617,Q619 and D603,D605,D607,D609,D611,D613 .
  9. dorke

    Ozone machine Repair

    Bad solders marked with Red good ones are like the Green. What was connected on the Yellows? What is written on Q1 and Z1 ?
  10. dorke

    Ozone machine Repair

    Well, Now you did post. The soldering quality of the pots is very poor. Look here and learn how to. Take your time learning,soldering quality is critical for repair. What is the brand and model name of your unit?
  11. dorke

    Amp In Protection Mode

    You can, but there is no need to, simply pull out C613 alone (leave C617 in for starters) and check without a cap in it's location. A few notes: 1.The Print-Side looks very nice,no visible problems. 2.R627(Blue) is lifted and not connected,at this stage it should be connected to GND. 3.The...
  12. dorke

    Ozone machine Repair

    Welcome to EP. Maybe we can help. Do you have a service manual or schematics of the unit? Some photos could help as well.
  13. dorke

    Amp In Protection Mode

    O.K As I suspected ,the reading on R623 is indeed wrong, there should be no DC current through it (hence no voltage on it). Please take a good photo of of R623,C613,C617 and vicinity. Please take a good photo, of the solder side of R623,C613,C617 and vicinity. Could be dirt oxidation or...
  14. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    The warning symbols have nothing to do with current adjustment. Only to use same type and rating of resistors((non-flammable etc.) Although it is a very good idea to start with drive at minimum,we should do that next time.
  15. dorke

    Transformer primary voltage exceed the rated voltage

    You should define "exceeds". It is normal for the input to have a "swing" of say 5% . In this case nothing happens,nothing is burned ,the secondary voltage will "swing" in the same %. If however,in the case that the transformer is not primary fused and the voltage exceeds significantly, the...
  16. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Please double check that you have mounted Q631,Q633,Q635,Q637 the correct parts. Please Remove Q635 from the board, and measure ,all in board,in diode test mode: Q621,Q623,Q627,Q629,Q631. D615 ,D617.
  17. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    These are completely different case styles will not fit physically. It may be,just may be ,the Trs are fakes. I would concentrate on finding all faulty devices before buying anything else.
  18. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    I don't know why ,I sure hope those bat-wins you got are not Chinese fakes. We should find all blown parts before we go replacing anything again.
  19. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Yep, Q635 is a goner,I would expect Q631 to be one as well.
  20. dorke

    Technics SA-828 Receiver from 70s- Is it worth trying to save this aging patient?

    Yes, Q635 is the relevant bat-wing.
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