Hi everyone!
Troubleshooting SMPS with output voltage fluctuation from 4.8V to 5.0V, spikes to 5.2V and back to 4.8 every 2-3 seconds.
Replaced with brand new: both optocouplers U6501/02, rectifier D6515, U6503 IC.
Primary voltage is stable 160V on C6506.
T6501 secondary winding output AC voltage is stable
Diodes tested OK. Caps OK. Resistors OK.
Suspect D6524, but not sure....
Any help is greatly appreciated!...
ponteley
New Member
Last Activity: 08-04-2021, 08:27 AM
Joined: 05-19-2020
Location: USA
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Yamaha TSR-7810 receiver power drift
Apparently same as RX-V681/RX-V781/RX-A760/RX-A860
Everything working fine when plugged in and turned on.
Output voltages on all speaker terminals are few mV.
As time goes by (10-20 minutes), FR chanel goes to 10mv>100mv>200mv>300mv and up to 3V and then PROTECTION kicks in.
Very strange issue. Can't find anything blown/overheating/shorted/open.
All diodes and transistors checking out OK. Resistors too.
Can't find service manual or schematic....
Any help is greatly appreciated. -
Yamaha RX-V483 - dead
Yamaha RX-V483 dead. No 5.5V on secondary.
Tested all fuses, diodes, transistors and caps.
Unsoldered transformer, - seems to ring trough on all coils. Fuses are OK. Primary DC voltage 160V. I suspect 3A453 IC, but I can't find replacement or substitute anywhere.
Please help.
Thank you....Last edited by ponteley; 05-20-2020, 06:34 AM. -
Re: New Members - please post your introductions here
New member here. Need help with broken A/V receivers.
Thank you!
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