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]

I can confirm for now that when the board is connected, as well as the power ON, the IC goes up to 98F and the bead to +/- 88F, whereas everywhere else, it's less than 75F.

seems to be ok based on the IC datasheet:

 

[wilder1626]

OK, then. I continue my investigation. I may have put my finger on a potential problem. Please let me know what you think.

When I disconnected the cable between CN112 and CP2200, by pressing the Power button, it turned on without any problem. So I suspected the problem before CN112 . So, without removing the MAIN ASSY board from the chasis, I used my multimeter to see if I was getting the 12v on pins 1, 2, 3 of CN112, and that's not the case. So I think the problem is prior.

This brings me to this part of the diagram:

I now suspect that numbers 2, 3 and 4 in the picture above could be the source of the problem.

I would then have the remove the board to test it as i cannot do it from above.

 

[Nigel Goodwin]

I don't see how just randomly guessing at components is going to help?. But of those three numbers, 2 & 3 certainly wouldn't ever go faulty, nor would they cause any problems if they did. Number 4 'could' potentially fail, electrolytic capacitors are prime failures - easily checked as long as you can get to the top of connector CN112, just push the wires of a suitable through-hole electrolytic into the connections on the top, see if that cures the problem. Doesn't need to be 10,000uF, anything in the range 1000uF to 10,000uF should be fine.

 

[wilder1626]

I've already tried several times, and I confirmed that the CN112 wires are correctly inserted.

May I ask why you're talking about "randomly guessing at components"?

I'm just trying to follow what I think is a logical path to try to find the origin of the problem, because it's not obvious.

I notice that I'm not getting any voltage from my CP113 from the transformer when it's on standby (not powered up). This doesn't seem normal to me. Should I normally be getting some voltages? Normally +12v.

 

[Nigel Goodwin]

I've already tried several times, and I confirmed that the CN112 wires are correctly inserted.

???? - I mentioned no such thing, read my post again.

May I ask why you're talking about "randomly guessing at components"?

R285, C293 - random components - neither of which would ever fail, nor cause your problem if they did.

I'm just trying to follow what I think is a logical path to try to find the origin of the problem, because it's not obvious.

I notice that I'm not getting any voltage from my CP113 from the transformer when it's on standby (not powered up). This doesn't seem normal to me. Should I normally be getting some voltages? Normally +12v.

My first thought would be no, if it's in standby then the mains supply voltages will be turned OFF, probably by a relay. You usually have two transformers, a small standby one, and a large one for actual power.

 

[wilder1626]

???? - I mentioned no such thing, read my post again.

First of all, my sincere apologies. I did misread what you said.

I will start by checking the no 4 (electrolytic capacitor).

 

[Nigel Goodwin]

First of all, my sincere apologies. I did misread what you said.

I will start by checking the no 4 (electrolytic capacitor).

I described the easiest way

 

[rjenkinsgb]

I can confirm for now that when the board is connected, as well as the power ON, the IC goes up to 98F and the bead to +/- 88F, whereas everywhere else, it's less than 75F.

If those ferrite beads near the HDMI port are heating up at all, it sounds like a short (or partial short) in the HDMI connector or the C2261 / C2263 caps at the connector side of the beads?

 

[wilder1626]

If those ferrite beads near the HDMI port are heating up at all, it sounds like a short (or partial short) in the HDMI connector or the C2261 / C2263 caps at the connector side of the beads?

Thanks for your advice. I'll check it out closely next weekend.