Yamaha RX-V359 troubleshooting, turns on and off

[Jooo]

Re: Yamaha RX-V359 troubleshooting, turns on and off

A faulty Q109 accounts for the missing -49 volts. A missing 1.2 volts on pin 8 might be caused by missing +48 from Q108/R133. Q106 serves as the 1.2 volt regulator.

Thank you for your message.

R133 was ok.
Q108 and Q109 (2SB1274) are same parts, I ordered two yesterday and will replace both.
I ordered Q106 (2SA949) too just in case, not expensive so might aswell replace it while I'm at it.

[Longbow]

Re: Yamaha RX-V359 troubleshooting, turns on and off

Thank you for your message.

R133 was ok.
Q108 and Q109 (2SB1274) are same parts, I ordered two yesterday and will replace both.
I ordered Q106 (2SA949) too just in case, not expensive so might aswell replace it while I'm at it.

A simple diode test with a multimeter would have confirmed if any of those transistors needed to be replaced. Most often you won't have to pull them out either.

[Jooo]

Re: Yamaha RX-V359 troubleshooting, turns on and off

Yes I did know that, Q109 was bad and R144 10ohm resistor just before Q109 measures megaohms.
Since there was minimum order limit and I didnt really need anything else, I thought it wont hurt to replace some of the other parts too.
Still waiting for them, should arrive this week.

[Jooo]

Re: Yamaha RX-V359 troubleshooting, turns on and off

I replaced the parts listed, and I have good news, but also bad news.

Good news: It's alive!
I tested it for a few minutes on FM and it seems to work just as it should. I didn't test it longer because I didn't want to make it worse than it already is, because:

The bad news: Although it does not shut down now, I checked the diagnostics mode. Sure enough, there still seems to be something wrong: DC PRT value has gone up to 75 percent...

What could be causing this or is it normal that the DC PRT value is so high? Why it does not shut down to protect itself? Is it safe to use?

[Longbow]

Re: Yamaha RX-V359 troubleshooting, turns on and off

Why not check the d.c. at the output terminals? The error codes in the unit might remain in history until they are cleared - that's just a guess.