Stereo Receiver Protection Relay Closes Too Fast on Sansui G-7000 Receiver

Discussion in 'The Projects Forum' started by Zekemann, Dec 16, 2013.

  1. Zekemann

    Thread Starter New Member

    Dec 16, 2013
    5
    1
    I picked up a Sansui G-7000 receiver last month. All original for restoration

    I noticed the first time I powered it up that one replay clicks instantaneously upon hitting the power switch and then it takes several seconds for the second replay to click in. (The schematic shows two relays - and inrush relay and a speaker protection relay). Subsequent power-ups had both relays sometimes clicking quickly together and other times the relays click with an normal interval of time between each ones engagement.

    I decided to open it up and clean it off. I recapped the power supply board last night and the driver board ...same issue!

    Bottom line is that the protection relay is closing too early!! My question for you technical experts is; What would cause the protection relay to close TOO quickly?

    Thanks for any advice!!
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,006
    3,232
    Perhaps there's a bad capacitor in whatever circuit controls the delay for the protection relay.
     
  3. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    C609 or C617, depending on which relay.
     
  4. Zekemann

    Thread Starter New Member

    Dec 16, 2013
    5
    1
    Well gents I really appreciate the quick response. ...and we have a Sansui fan here as well?? I did recap the power suppply and driver board but I will need to go back and take a look at these two caps and report back!

    Thanks,

    Zeke
     
  5. Zekemann

    Thread Starter New Member

    Dec 16, 2013
    5
    1
    I reviewed the schematic and both C609 and C617 are brand new caps.
     
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,031
    3,802
    May be new, but are they the correct capacitance? Did you measure their values or do they just look new?
     
  7. Zekemann

    Thread Starter New Member

    Dec 16, 2013
    5
    1
    Yes... I installed brand new caps of the same capacitance. The unit exhibited the same issue with both old and new caps.
     
  8. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    The associated zener diodes would be worth checking.
     
  9. Zekemann

    Thread Starter New Member

    Dec 16, 2013
    5
    1
    You are correct. I just replaced the one closest in series to the relay and it resolved the problem!

    Thank you guys very much!!

    Zeke
     
    KJ6EAD likes this.
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