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Yamaha CR-1020 Relay Issue

Discussion in 'Yamaha' started by Bluhn321, Mar 5, 2016.

  1. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
    Oshkosh, Wisconsin
    My bad I realized I measured incorrectly. So I actually got about 49.3 v DC for the emitter and base on both transistors. Just to be sure I did this correctly I use the red probe on the emitter or the base and the black probe on the bare chassis?
     

     

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  2. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
    Oshkosh, Wisconsin
    Not sure if this would help but when the unit is powered on the two power meters go all the way to the right and hold there.
     
  3. petehall347

    petehall347 the brandy coffee man Subscriber

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    Location:
    uk.. the middle bit
    i take it that is positive voltage ? that is important too .
    there should be a grey wire goes to the board and the trace heads off towards r603 . see if you can find r603 and measure the voltage each side ..one side should be -91v the other side -57.9 .
     
  4. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
    Oshkosh, Wisconsin
    Yes, it is positive.

    I got -93.8v and then -63.8v
     
  5. petehall347

    petehall347 the brandy coffee man Subscriber

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    i am turning in for the night so if avionic is around to help or anyone else ....
     
  6. avionic

    avionic " Black Knights " Subscriber

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    Hmm..
     

     

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  7. avionic

    avionic " Black Knights " Subscriber

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    Pull TR611 and 612 and test them with your meter.
     
  8. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
    Oshkosh, Wisconsin
    They both check out good.
     
  9. petehall347

    petehall347 the brandy coffee man Subscriber

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    i am suspecting out of tolerance resistors . there is at least 1 fuse resistor according to the schematic . fr601 100ma 68 ohm best check them .
     
  10. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

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    Location:
    Oshkosh, Wisconsin
    Is this resistor on the main C. board? Or is it somewhere else?
     
  11. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

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    Location:
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    Alright I found it. It tests at 68.8 ohms.
     

     

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  12. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
    Oshkosh, Wisconsin
    Well I have some good news. Just because I thought "what the heck" I replaced the output transistors with ones that came from another 1020 I have that works and the relay clicked on! I tested the outputs to be sure there isn't any DC output and that checks out good. So it looks like I'll be looking for some replacements. But now I have another issue. Even though the relay clicks the meters still max out to the right and stay there. They change and go back to normal it seems when the toggle switch is pushed in for them to show tuning signal.
     
  13. avionic

    avionic " Black Knights " Subscriber

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    43,656
    Location:
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    Have you got the volume control fully CCW.
     
  14. avionic

    avionic " Black Knights " Subscriber

    Messages:
    43,656
    Location:
    Fort Dodge, Iowa
    If the relay "clicks" there is no DC on the output.
     
  15. petehall347

    petehall347 the brandy coffee man Subscriber

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    Location:
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    troubleshooting the meters looks like fun .
    do you have headphones ? if so is the sound good from them ? i dont think this is really relevant but will be good to know anyway .
     
  16. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
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    Yep, the volume control is all the way CCW. The meters go to the right on power up even if nothing is plugged in.

    I'll test out the headphone jack here shortly.
     

     

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  17. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
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    so they both go right up and stay there ?
     
  18. Bluhn321

    Bluhn321 Hockey: Making dentists rich since 1875 Subscriber

    Messages:
    234
    Location:
    Oshkosh, Wisconsin
  19. clearsoft

    clearsoft New Member

    Messages:
    9
    I had a similar issue with my CR-1020; intermittent popping from both channels and a bit of low level hum at initial turn on. Read every post here for Yamaha CR relay/no sound/clicking and viewed many youtube videos. Many many hours of troubleshooting, so wanted to share here in the hopes of saving others some heartburn.

    After a full power supply recap (both pcbs) and power transistor upgrade to higher voltage TIP31C in the supply, the protection relay would not fire. The -25V output sat at -10V. Cleaned the flux and grime off the bottom side the PCB and the output went to +6V. Disconnected the two purple wires from the -25V post to eliminate loading. No improvement. Removed and retested all 4 transistors; junctions not shorted nor open.

    Decided to look at the .01uF capacitors. In circuit across the terminals, the one on the -25V supply measured 6 kOhms whereas the one in the +25V supply measured 3 megohms. Pulled the caps; neither was leaky. Pulled the 4 transistors again. Still 6 KOhms...strange.

    Used flux remover to clean the top side of the PCB around the .01uF cap locations, removing glue residue around the heatsinks. Resistance now 2 megohms. Apparently the glue that Yamaha used was not electrically benign and the -25V supply is extra sensitive to leakage current (check out the circuit topology).

    Reinstalled all components. Reconnected all wires. Voltages perfect. Relay works.
    —Ed
     

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