Yamaha RX-V559 wont turn on

[filip0502]

I have a Yamaha RX-V559 that suddenly stopped showing signs of life. First, it wouldn't turn on, and then I unplugged it from the wall for a few minutes. When I plugged it back in, it started working. Now it doesn't work at all.

When I press the main power switch, nothing lights up. I don't hear the relay clicking.

I looked at the transformer and I don't think that the internal fuse is blown since it's not showing an open contact on the primary side.

The 2 fuses on the power board aren't blown either. None of the capacitors and transistors look burnt. I tried measuring the voltage on an IC on the board, and I got around 7.5V so the transformer is definitely supplying power.

Does anyone have an idea what I should look at or measure? I looked through the service manual, but I didn't find any voltage references. I don't know if there is a problem with the relay, maybe, or the standby power button circuit

 

[mbz]

Did you check the diagnostic function for any protection info? Page 19-21 of sm.

Unplug the unit from power, allow 30-60sec then reconnect to power.
Press/hold down the INPUT MODE and MULTI CH INPUT, while still holding these down press the power on/standby button then relase all.

Note the message displayed
eg
PS1 PRT:nnn

Need the full message, protection type PS1, PS2, DC, I,,, and the numbers nnn

 

[filip0502]

Did you check the diagnostic function for any protection info? Page 19-21 of sm.

Unplug the unit from power, allow 30-60sec then reconnect to power.
Press/hold down the INPUT MODE and MULTI CH INPUT, while still holding these down press the power on/standby button then relase all.

Note the message displayed
eg
PS1 PRT:nnn

Need the full message, protection type PS1, PS2, DC, I,,, and the numbers nnn

Nothing happens. The screen doesn't turn on at all.

 

[mbz]

As shorthand I will refer to reset the amp, by this I mean unplug the amp, wait 30-60 seconds then plug it back in. A smart way to do this is to plug the amp in a switched terminal board then use that switch.

Reset the amp, reconnect to power (do not attempt power on the unit)
Measure dc voltage at connector
W3009 Page 85 co-ordinates 4I
pins S10, PDET, +5M, /RES
Expect S10 =10V, and 5V for the rest.

Monitor the voltage at the PRY pin then attempt to power on the unit itself (POWER ON/STANDBY button)

edit Its that orange 8 pin connector, east of the relay shown in post #1.
You will probably need a fine point on your probe. I usually clamp a pin or sewing needle or component leed off-cut to the probe, use some insulation, stripped from some wire as the clamp