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Yamaha reciever power issue

Discussion in 'Troubleshooting and Repair' started by Shadow, Aug 7, 2013.

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  1. Shadow

    Shadow

    2
    0
    Aug 7, 2013
    Hey guys, I have a Yamaha hrt-5860 that blew a fuse when I hooked up some bad speakers...just trying something out and it went wrong lol....Well I replaced the fuses and it still wont turn on, just clicks, I can only press it 3 times before it stops clicking. Any suggestions?
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,496
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    Jan 21, 2010
    Unfortunately I suspect that some of your output transistors died in a valiant effort to protect the fuse, but failed.

    You need to check (at the very least) that there are no other internal fuses, but I would be checking the output transistors to see which ones are now short circuit.

    The failure may have taken out more than one component.

    Your next step may be to send it in for repair. If you decided to do it yourself then you will be best advised to try to locate a service manual and/or a schematic for the amp.
     
  3. Shadow

    Shadow

    2
    0
    Aug 7, 2013
    How would I begin to check components and which are output transistors? I can fix most electronics on my own, replaces ICs in my LED when it stopped working. Soldering is easy seeing as I do it everyday lol. If I could get guided through what to look for I can replace parts.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    The output transistors are most likely going to be large three-legged devices attached to large heatsinks.

    You need first to identify them, then to determine what sort of transistor they are (they could be something else...). Based on that you test them.

    The best start is a nice clear photo of the insides of your amp. If you can identify the output transistors (there will typically be a multiple of 2 per channel) take a close up photo of them so we can read the part numbers.

    This view of them may even tell us that some have been destroyed.

    Take photos in indirect light (i.e. not flash or direct sunlight.) Outdoors in shade often works really well. We need to be able to read what's on the components.
     
  5. elebish

    elebish

    177
    12
    Aug 16, 2013
    Check the emitter (thermal runaway) resistors. They are usually about a half ohm at several watts. I would also check the driver transistors. The "clicking" is usually a protection circuit that shuts down the power supply when something shorts out.
    You might try putting a 75 or 100 watt incadescant light bulb in series with the 120 vac that powers the receiver. If the bulb lights up brightly and stays bright, you still have a short somewhere in the receiver. The lamp is a positive temperature coefficient (ptc) device that increases in resistance when it gets hot and will lower the current to the receiver. This should protect your receiver. Ed.
     
  6. elebish

    elebish

    177
    12
    Aug 16, 2013
    Ensure that the total speaker impedance is NOT less than 3 ohms! Ed
     
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