Pioneer AV Receiver VSX-324 Power button issue

[wilder1626]

Hi all.

I have a Pioneer VSX-324 AV receiver whose only problem is the power button.
Schematic of the receiver: https://www.manualslib.com/manual/1027739/Pioneer-Htp-072.html?page=1#manual)

The problem I'm having is that when I use the remote to turn on the receiver, I just hear a click, but it doesn't turn on.

The only way to turn it on is to hold down the button for 2-3 seconds and it turns on without any further problem.

Holding the buttons down, I hear the clicks every fraction of a second, about 3-5 clicks. Then it turns on.

This problem started one day when I wanted to activate the receiver and TV using the remote control.

As far as I know, I've never had a power cut or power surge, nor a cable change. I have no other problems, such as sound quality or anything else.

I'm thinking that the problem may come from the button connection himself or maybe in that part of the circuit.

Do you have any ideas on how I should start looking for this problem?
Any help would be greatly appreciated.

Thank you very much.

 

[wilder1626]

Thanks again for your feedback rjenkinsgb

I will find that problem one day.

I'm even wondering if this isn't the reason why all my HDMI ports on my TV was no longer working, since i was no longer having a signal on each port all at once. In fact, I had to change the IC chip for the HDMY ports on my TV.

Ok, I'm going to remove the MAIN ASSY. I think I'll find the problem on this board.

 

[wilder1626]

Something's not quite right. Since, on standby, when I click once on the power button, it doesn't want to light up, and since I don't have an HDMI LED flashing, and since my F301 fuse isn't open, then I checked on pins 6.9 (C301 + side) of the STBY Assy CP701, and I'm getting +10V when I should be getting +5.6V.

So if I understand correctly, and if I'm right, it's automatically a problem with the Assy STBY generating 10V. So if I trace the voltage of the power cable to the C301, which has 10V in stand-by mode, I have 2 NPN transistors (LF and N5).

So I decided to validate the reading I get on each of them, and it seems that the LF transistor may have a problem. I'd like your opinion on this:

Is it possible that the values in red are the cause of a no-start problem?

 

[wilder1626]

I can also see that the 2 diodes just after the relay pins, and before the 2 transistors are diode A6, and no matter which way the black/red probes are , I get 0.590 / 0.620 values in diode mode (test on circuit board). Normally, I should get a value on one side, but OL when I've inverted the probes. Correct?

So since the relay works, I can hear a click, and it has also been changed and tested, the problem seems to be with either the diodes or the transistor, or both.
What do you think?