Pioneer VSX-3300 Receiver Wont Power On

[budwich]

Re: Pioneer VSX-3300 Receiver Wont Power On

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

[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

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".

[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

[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

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.....

[lotas]

Re: Pioneer VSX-3300 Receiver Wont Power On

All 4 diodes D551-D554 check out ok, neither open or shorted......

Diodes, zener diodes, transistors may be leaking or cut off under voltage, load, and the multimeter will not show this.

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

If you are measuring 11vac feeding the diodes, you should have about 15.5 volts Dc across the capacitor. Do R569 or R570 or Q551 seem to get warm/hot? You should have about 5v across D555 so maybe the zener is bad C551 is bad
Unplug J9 and see if the voltages come up

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

All 4 diodes D551-D554 check out ok, neither open or shorted......

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

AC voltage on pins 4 and 7 of the transformer are reading 10.9VAC

[lotas]

Re: Pioneer VSX-3300 Receiver Wont Power On

If you cut the track, the voltage rises to C 552.

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

Measure the AC voltage across pins 4 and 7 of the transformer, it should be at least 11VAC, Check that you don't have an open or shorted diode D551 ~ D554

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

I just re-soldered all the legs of the transformer, no change..... still 11.3v

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

I replaced C552, actually it was one of the first things I did, and I only have 11.3v across C552

[lotas]

Re: Pioneer VSX-3300 Receiver Wont Power On

Try to solder the legs of the transformer, ring cracks may form (cold soldering).

[R_J]

Re: Pioneer VSX-3300 Receiver Wont Power On

Start by replacing C552, it is likely open and causing ALL the voltages to be low. You need about 16VDC across C552

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

There actually is no switch for 120/240, it's 120v only......

[lotas]

Re: Pioneer VSX-3300 Receiver Wont Power On

Is your switch set to 120v correctly?

[thetonywarren]

Re: Pioneer VSX-3300 Receiver Wont Power On

tested everything again, with using the negative on the capacitor negative terminal and get the same readings.....I then took R569 out of circuit and it's measuring at around 82 ohms.......

[eccerr0r]

Re: Pioneer VSX-3300 Receiver Wont Power On

There was someone on another forum that was doing tests with the chassis ground and it just so happens the chassis ground is useless for measuring. Ended up having to throw out all the measurements as invalid! In modern devices, this is less of a concern because it's typically connected to negative anyway. To be certain, all of the electrolytic capacitors on that board - the negative terminal - should all be connected to ground and you can use that as the reference point.

That transistor Q551 might be that C3377 TO-92, so if facing the flat side and pins downwards, the leftmost is emitter, center is collector, and right is base. Because you're getting low voltages on everything (assuming the above is checked) I'd suspect R569 fried. R569 supposedly is that one parallel to the longest edge of the board that's closest to the big capacitor.

and that's pushing it for a ½W unit...

Do test the transistor as well, diode check the junctions and make sure it's not shorted.