Pioneer VSX-3300 Receiver Wont Power On

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

R569 is very hot, but when I tested it out of circuit it was approx 82 ohms, like it should be. I tested across the capacitor after removing one leg of R569, and the voltage to the capacitor did rise to 15.3V. I checked voltage across D555 and it's only around 3.4V, and when I take C551 out of circuit and test with ESR it is about 46uf.....

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

If R569 is very hot, I suspect there is too much of a load on the emitter side of Q551.
Did you unplug J9 and see what all the voltages are around the Q551 regulator?
If the 5 volts comes up with J9 disconnected, reconnect it and remove one end of D558 then D559 to see which line is loading down the circuit

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

I had to unsolder J9 as it doesnt have a connector, oh well.... when I unsoldered it, I do have 5v on J9. I re-soldered J9 and removed one end of D559 first and checked voltage, it was at around 2.3V, then reconnected it, and removed one end of D558 and checked voltage and its around 1.2V both were checked at J9

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

do you have a transistor checker? Check q551. Also, with power off / disconnected, do a resistance measurement at the connector for the 5v supply to see what impedance is on the circuit. disconnect the two 5v circuit at the connector to measure each one seperately to see if there is a significant difference in impedance on each "leg".

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

I had to unsolder J9 as it doesnt have a connector, oh well.... when I unsoldered it, I do have 5v on J9. I re-soldered J9 and removed one end of D559 first and checked voltage, it was at around 2.3V, then reconnected it, and removed one end of D558 and checked voltage and its around 1.2V both were checked at J9

I thought J9 was a plug. anyway, J9 has 6 wires, which wire's did you remove to get the 5 volts to come up?
You can leave them attached and remove D558 and check the voltage on Q551 emitter, Then remove D559 and check the voltage on Q551 emitter, if the voltage is still LOW, remove the wire on J9 labeled tuner and check the voltage on Q551 emitter.

Once you isolate the line that is getting loaded down you can track down the bad component

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

check the c617 capacitor in the 5vBU path further in the circuit.

[CapLeaker]

Re: Pioneer VSX-3300 Receiver Wont Power On

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

[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

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

[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!

[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

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.....

[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

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

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.

[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

[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

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)

[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?

[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,