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Electronics => Repair => Topic started by: dbgeek on January 15, 2025, 12:48:56 pm

Title: yamaha RX-V579 dead no power
Post by: dbgeek on January 15, 2025, 12:48:56 pm
Hi,
bought a dead RX-V579 ,do get 5.5 volts from rail but no +3.3 volts on the rail that powers Relay ,service manual that I downloaded is incorrect as it shows voltage checks for a non -US receiver https://elektrotanya.com/yamaha_rx-v579_tsr-5790.pdf/download.html
have replaced both 47nf caps C5408,C5409,online folks have said that it may be C5405 .Not sure how to troubleshoot this issue.
Fact that 5.5 volt rail is working tells me that Primary transformer on power supply is working only issue is to get +3.3 volts working for PRY to work I guess
Thanks
Title: Re: yamaha RX-V579 dead no power
Post by: tom66 on January 15, 2025, 01:13:03 pm
I had this with my old Yamaha (RX-V457) and ultimately concluded it was a dead microcontroller, so it went to the e-waste pile in the sky.  Check the processor board is regulating the 5.5V down to 3.3V for the microcontroller.  My 3.3V supply was present but all signals on the MCU were dead, including relay on signal, I later found online this does occur sometimes, perhaps power surge damage or bad flash cells degrading.  In theory a new board could fix it, but I couldn't source one.  The RX-V579 is a much newer generation though so you may have better luck, good luck either way.
Title: Re: yamaha RX-V579 dead no power
Post by: FIXITNOW2003 on January 16, 2025, 07:27:40 am
https://www.hifiengine.com/hfe_downloads/download.php?yamaha/yamaha_rx-v579_tsr-5790_service_en.pdf (https://www.hifiengine.com/hfe_downloads/download.php?yamaha/yamaha_rx-v579_tsr-5790_service_en.pdf)
Title: Re: yamaha RX-V579 dead no power
Post by: dbgeek on January 17, 2025, 03:49:16 am
sorry I am not able to download as hifi site disabled new user creation, I accidentally disconnected connector from micro and after connecting I do see 3.3M but still cannot power up the system.
when I tried jumper on relay I do hear click on amp relay but nothing happens, should I be checking any other part/s for voltage as I am guessing issue is with not powering relay on standby and amp/regulator needs to checked
Title: Re: yamaha RX-V579 dead no power
Post by: tom66 on January 19, 2025, 10:18:54 pm
Can you upload that PDF directly? I can't access it.