Blowing fuses in 919.....Any ideas?

Discussion in 'Exclusively Sansui' started by ghamilton, Mar 31, 2017.

  1. deltalight

    deltalight AK Subscriber Subscriber

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    Were the 4 oval caps ever rebuilt?
     
  2. ghamilton

    ghamilton Super Member

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    no
     
  3. AUD101

    AUD101 Parsley The Lion!

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    Balance adjustment without distortion meter - Set VR01 to 2/3 position from max. point & Set VR02 to 2/3 position from min. point
     
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  4. ghamilton

    ghamilton Super Member

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    I know. Thanks
     
  5. ghamilton

    ghamilton Super Member

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    Last edited: Apr 6, 2017
  6. _mano

    _mano Active Member

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    Sorry to hear about your AU-919.
    NMA1012 is the PNP - Collector of this goes to the -ve power rail
    NMC1012 is the NPN - collector of this goes to the +vc power rail

    Very Strange, why this became shorted.
     
  7. ghamilton

    ghamilton Super Member

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    Only one NPN and one PNP was bad on one channel. I replaced all outputs anyway. Now on to the transistors on driver board. Is there a way of checking them without taking them out? Also, I,m looking for a 919 modern transistor sub list. Thanks again guys.
     
    Last edited: Apr 7, 2017
  8. ghamilton

    ghamilton Super Member

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    I can't find a transistor replacement list here on AK. Can someone help me find it?
     
  9. AUD101

    AUD101 Parsley The Lion!

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  10. ghamilton

    ghamilton Super Member

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    Thank you! I knew I saw this before but I couldn't find it. I guess if the exact wording isn't used when searching then no luck. Thanks again!
     
  11. ghamilton

    ghamilton Super Member

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  12. petehall347

    petehall347 the brandy coffee man

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    change both drivers and use complimentary to keep the balance .
     
  13. ghamilton

    ghamilton Super Member

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    If your talking about TR 29-30-31-32 yes I will replace all 4. However, I'm concerned about performance specs. Can anyone tell me if the link on the modern replacement is a good choice?
     
  14. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    You really don't have a lot of choice unless you can find NOS originals, the substitutes suggested, although overkill in respect of their basic specs, have the important metal tabs, (TO220 case) which is the same arrangement as the originals. There are other replacements with similar spec's like KSA1220A (PNP) & KSC2690A (NPN) - but they don't have the metal tab (TO126 case) - so your installation of these types needs to take account of this.
     
  15. ghamilton

    ghamilton Super Member

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    Thank you so much Hyperion. I was beginning to think that no one was going to help me.
    OK, I will use these modern replacements hoping the performance will not degrade. I am building a list of parts to order. I hope it won't be a big one. Thanks for your help and keep checking back!!
     
  16. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    The performance won't degrade - they are very good replacements, just the nerdy perfectionist in me speaking with regards to the differences in the replacements. :)
     
  17. Overundr1

    Overundr1 AK Subscriber Subscriber

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    Watching and reading along, however never having one of these on the bench deferring input to others that have already been down the 919 roadway.
     
  18. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    As you may know I've reconditioned 3 but never had to deal with a seriously faulty one. :)
     
  19. ghamilton

    ghamilton Super Member

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    Just ordered parts today! Been busy with family matters.
     
  20. ghamilton

    ghamilton Super Member

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    While we,re waiting on those parts, I have a question concerning the noise in the MC stage. So far the only thing that I can think of after checking for shorts or arcing on the traces or bad solder joints,...Is a leaky transistor. I don't hear the noise if the phono cables are unhooked. I only hear the noise in the MC position and with the TT hooked up. The sound is a faint scratchy arcing sound in the right channel. My $1500 Grado low output Statement/reference sounds awesome but you can hear the noise between cuts. Only when I turned the volume past half way with stylus off the record to listen to the noise to try to figure it out did the amp make the zzzzt sound and go dead. Could a leaky transistor on the MC board cause this?
     

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