Pioneer VSX-3300 Receiver Wont Power On

[budwich]

Not sure how easy it is to get at c617, but that would still be my guess based on your posts. Its a 5.5v which might be pushed if there was any issue with the 5v lines.

not sure what the 5vbu serves .... does the unit turn on with it disconnected?

[thetonywarren]

It's a complete pain in the butt, but I did get it out and took it out of circuit. I have a basic meter to test it, but it doesnt go high enough to test.....this one is rated at 47mF 5.5v. My cheap capacitance meter only goes up to 20mF......

Any suggestions??

[CapLeaker]

Disconnect part of the 5Vbu, I d would like to see that the microprocessor still works. The 5Vbu splits, feeds the microprocessor on end and goes to the 100ohm resistor and a capacitor C617 in series on the other board. So lift that 100 ohm resistor and turn the unit on and see if the voltage stays. If C617 is bad, it will sour your day too. Follow the line a bit further down and you get to the Power Transformer and a fuse, check it.
I might have a bad feeling that the microprocessor is bad. If there would be a lot of current drawn from the other board, that 100ohm resistor should be toasty warm.

[budwich]

IF you disconnect the resistor in question, you can again do the simple resistance check towards the rest of the circuit (microprocessor) just like did previously and see what it gives you there in. That might tell you something about the processor electrically.... maybe.

[thetonywarren]

Ok, so I re-soldered in the information screen/panel re-soldered in C617, re-soldered in C706 and then I removed one leg of the 100 ohm resistor at R613.
after I did that, I pressed the power button and it turns on.....hopefully this gives us a better idea of what's going on.....

Thanks!!!

[CapLeaker]

That means the microprocessor is ok and the problem is below the 100 Ohm resistor. Did you check C617 to see if it is still good?
Actually take some voltage measurements at the microprocessor.

[CapLeaker]

It’s gotta be that c617 cap. It goes to gnd. Change it and see what happens.

[thetonywarren]

I have one of the cheap multi-function testers and you can see what shows on the screen, looks like it's testing at 34mF, seems low to me, but not sure with this size of cap.....when I look for replacments, I dont see any of similar size, all I can find are supercaps? Is that what this one acutally is, they seem to have different physical sizes than the one I have here.......

[budwich]

good work... size isn't necessarily an issue except maybe fitting to the board / mount. You might have to do some mod (ie. jumpering, glue, etc). look for something with the same capacitance and move up in voltage... it will likely be smaller physically (also due to advances in technology).

[thetonywarren]

This is what I purchased.....see attached screengrab.....I couldnt find a suitable substitute with a higher voltage rating, so hopefully this one should do......

[budwich]

hmmm... might not work. I don't see that it is an electrolytic (ie. polarized) which I believe the c617 is. You need to check that.

[R_J]

That cap is likely bad, it is a super cap 47mf/5.5v, mille not micro farad used for backup. It is possible the cap has been discharged for so long it won't charge any more and loads the 5v line too much so the micro won't turn on.
You don't need to have a higher voltage cap in that position 5.5v is what it should be.

[thetonywarren]

Check page 2, and page 7, I think it is polarized, at least from what I can find......Hopefully I picked an ok one, cause I couldnt find any close equivalent on the electrolytic side of selection on DigiKey.......

[R_J]

Yes it is a polarized capacitor it acts like a backup battery in the circuit.

[thetonywarren]

ok, so I then think that the one I purchased is ok...... Now to wait for parts to arrive, man, I wish there were local places to get stuff like this......

[R_J]

This component is a bit rare these days, most equipment uses other ways to backup settings etc.

[RJARRRPCGP]

This is like Xbox, pre-360.

[CapLeaker]

That super cap is not really needed for function. It’s probably just to keep settings, time etc. With the super cap c617 removed, the 100 ohm resistor put back in place, the unit should work now fine. Looks like the old cap is “wet” on the bottom?

[thetonywarren]

What do you actually mean when you say the cap is "wet" on the bottom, Im not familiar with that term.....

Thanks for the help!

[petehall347]

Originally Posted by thetonywarren

What do you actually mean when you say the cap is "wet" on the bottom, Im not familiar with that term.....

Thanks for the help!

has it got a leaky bottom ?