Pioneer VSX-3300 Receiver Wont Power On

[CapLeaker]

Re: Pioneer VSX-3300 Receiver Wont Power On

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.

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

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!!!

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

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.

[CapLeaker]

Re: Pioneer VSX-3300 Receiver Wont Power On

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.

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

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??

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

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]

Re: Pioneer VSX-3300 Receiver Wont Power On

I pulled out both C706 and C708, both of them tested out to be good......

Additional info, yes, all other wiring is intact, although I did need to unsolder the front information screen/panel, to get at C708,

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

Ok, I connected it that way and checked the resistance, it slowly rises to above 2k ohms.......

if that is the 5vbu wiring point, that would appear to be ok as it appears that perhaps the cap is charging (by the meter). It is still possible that the cap is leaky when a more "capable" power source is applied (your meter may not have enough power to cause it to break down). Probably only a direct cap check will be necessarily.

Just for clarification, all other wiring is in place except for the 5vbu, and then you see a "normal" 5v at the supplying circuit (as expected).... OR you have disconnected all 5v wiring circuits?

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

That should be ok, but it could that one of the caps I suggested is shorting when 5 volts is applied, the other component that could be at fault, lets hope not, is ic701 (microprocessor)

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

Ok, I connected it that way and checked the resistance, it slowly rises to above 2k ohms.......

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

Check the resistance of the Back up line to ground, I suspect there are only 3 easy suspects, C706, C708 and maybe C617. I would start by lifting (unsoldering) one end of C706 and C708 and see if the voltage stay up.
Both caps are located on the front panel board near the main microprocessor's crystal

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

With power disconnected, you use the resistance measurement setting. measure with the red on the wire going towards the rest of the unit (which I assume is the one that you dsconnected) and black on ground / chassis. You should read something as described. IF you look at the circuit of the 5vbu, if the cap is bad, there is still a 100 ohm resistor in the path which you would see in some form... maybe.... depends on what's up.... could be a shorted wire path somewhere as opposed to a cap problem.

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

Please pardon my ignorance, but can you give me a little bit of guidance on how to do an impedance test? Im guessing setting my DMM on ohms and checking, but do I check the wire that I disconnected from J9, or on the board side of J9, and just check that along with ground? Sorry for sounding stupid, but I dont think Ive checked the impedance on a circuit before......

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

before you get going to far... just do an impedance test on the 5vbu line at the removed j9 area. It may tell you more... watch how the meter responds... looking like it is charging a cap, looks like a stable reading, etc.

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

Never mind, I was able to pull the front volume knob off, I wasnt pulling hard enough, just trying to be as careful as possible.....

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

so next question, I want to check C617, but I believe it's behind the circuit board thats contained in the front panel.... In order to get that circuit board out to look at it, I need to remove the front volume knob, because there's a horizontal circuit board for the volume knob in the way....does anyone know how to remove this board/volume knob assembly, Im not seeing any obvious connectors or way to remove the knob assembly.....I'll attach some pictures.....

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

Ok, sorry for being off the grid for a few days, Im back and available to test things further....

I did remove the first connector on J9, which is +5V BU, and it looks like the voltage comes back up, when I tested voltage at C552, I now have around 16.8V, so I would assume that's the path that's bringing it down?

Let me know your thoughts and next steps.....

Again, thanks to everyone for their help and assistance, it's greatly appreciated!

[CapLeaker]

Re: Pioneer VSX-3300 Receiver Wont Power On

Well there are 3 possibilities. 5v, 5v backup and the 5v for the tuner.

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

maybe something is sucking the 5V rail low on that relay board?

That is likely what is happening and that is why I suggested to lift the components to see which of the three lines has the problem, we'll see what happens.

[CapLeaker]

Re: Pioneer VSX-3300 Receiver Wont Power On

maybe something is sucking the 5V rail low on that relay board?