Yamaha CR-400

Discussion in 'Yamaha' started by truckrglenn, Sep 26, 2015.

  1. truckrglenn

    truckrglenn Lost Subscriber

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    I just purchased a Yamaha CR-400, as-is, that does not turn on. There wasn't a fuse in the back, so I installed a 2.0 amp fuse. The three internal fuses are good.

    First let me say that I'm not an electrician or a tech, and don't know all of the correct names and terms, but I have figured things out before. So, I guess that I'm a techs worst nightmare.

    Anyway, I'm guessing that the power supply, part # GA60604, is bad. Current is flowing to the transformer, but I'm not getting any power from it.

    Using a little AAA battery continuous tester shows that the power switch is good.

    Any ideas what else I should check or where I can buy a new power transformer? Or what power transformer from another Yamaha CR receiver would work in it's place?

    Whoever worked on this before is worse at soldering them I am.
     

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    Last edited: Sep 26, 2015

     

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  2. truckrglenn

    truckrglenn Lost Subscriber

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    RutRo, someone wired the switched outlet wrong. The switched outlet is always on.
     
  3. truckrglenn

    truckrglenn Lost Subscriber

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    Yay, thinking that I might have this figured out. Didn't see the fourth internal fuse, it was blown. Replacing that fuse and I got power. But turned unit off the back on, blew the fuse again.

    Looking at the solder job on the board it looks like two wires are touching. Out of time, but I plan on resoldering the power transformer wires when I get the time next weekend.
     
  4. avionic

    avionic " Black Knights " Subscriber

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    Do either of the two red LED's illuminate? All four of the incandescent lamps are probably burnt out.Thats not uncommon.
    Theres a pigtailed fuse in series with the back panel fuse. Check it with a meter and see if its still good.
    There are a couple 4Ω 300ma fusible resistors that might be shot. One is for the regulated power supply and the other is for lamps. FR701 and 702.
     
  5. truckrglenn

    truckrglenn Lost Subscriber

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    Thanks. The pigtailed fuse was blown. Replaced it, the unit turned on, had sound from the speakers, then the good old burning smell and the fuse blew again. Can't work on it again until next weekend.
     
  6. Rafael Spear

    Rafael Spear New Member

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    Hi Truckrglenn, I have the same problem with a CR-400, turned on, good sound and then the pigtail fuse blew again. What did you find in yours?
     

     

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  7. avionic

    avionic " Black Knights " Subscriber

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    What size is the primary fuse on the rear panel?

    What is your mains voltage Rafael?
     
  8. Rafael Spear

    Rafael Spear New Member

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    The primary fues is 2A, 250V and internally has another 2A welded to it. If you are referring to my power voltage to de receiver it is 115V. Thanks for looking into my problem. I just measured all the resistors in the Main power board and found that R603 and R604 are 11K Ohms instead of the 220K as called in the schematic. I haven't check the values vs color codes yet. Experiences and suggestions are very welcome
     
  9. avionic

    avionic " Black Knights " Subscriber

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    In circuit or out of circuit?
     
  10. Rafael Spear

    Rafael Spear New Member

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    in circuit
     
  11. avionic

    avionic " Black Knights " Subscriber

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    Last edited: Sep 16, 2018 at 9:48 PM

     

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  12. avionic

    avionic " Black Knights " Subscriber

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    I figured that.:biggrin:
     
  13. Rafael Spear

    Rafael Spear New Member

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    Yesterday I found pigtail fuse blown and replaced it, powered up the unit and blew up F703 but stayed powered, all lights were on, resistor R630 has signs of heat but still on 10 Ohms. Turned off and started the checking
     
  14. avionic

    avionic " Black Knights " Subscriber

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    Pull and check the right channel output transistors.TR616 and 618.
     
  15. avionic

    avionic " Black Knights " Subscriber

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    Check R638 and 640 emitter resistors as well ( .47Ω / 2watt)
     
  16. Rafael Spear

    Rafael Spear New Member

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    Pulled up TR618, + on Base (pin 1) and - on emitter (pin 3) = 1.4k Ohms, +E and -B = 2.1k Ohms. +B and -C = 1.4K Ohms, +C and -B = 2.1k Ohms, Collector and Emitter no resistance both ways. I have not pulled TR616 but when I measured it in circuit it doesn't present faulty values which are similar to what I measured in TR615 in circuit. R638 and R640 measured OK
     

     

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  17. avionic

    avionic " Black Knights " Subscriber

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    That looks bad to me.
     
  18. avionic

    avionic " Black Knights " Subscriber

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  19. avionic

    avionic " Black Knights " Subscriber

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    Also pull and check TR612 and 614 output drivers.
     
  20. avionic

    avionic " Black Knights " Subscriber

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    Feeds the collector of TR612
     

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