Pioneer VSX-3300 Receiver Wont Power On

[thetonywarren]

Have a colleagues Pioneer VSX-3300, it wont power on, hasnt for a number of years, but just now trying to figure out what's going on with it.

It has 120V input and I have followed that 120V to a small board that appears to have a small transformer and a relay among a few other components I dont think the relay is changing state which I believe turns on the receiver, but this is all speculation.....

I have downloaded the repair guide, which I have attached to this post, but I am having a hard time following it.... Can someone please offer any advice on what to check? Im pretty proficient with a multimeter and am good at soldering as well, so im not afraid of taking anything out of circuit to check if needed....

Any help is appreciated.

Thanks!

[CapLeaker]

I guess you have to be a bit more specific. Is it totally dead, is it in protect mode, are any fuses blown, is the power switch working, etc.

[thetonywarren]

Ok, I can definitely be more specific. It seems totally dead, but it has 120v power, and I can follow that 120v power to a relay assembly board inside, which seems to go through a small transformer and I think should turn on a relay, which powers the rest of the board. I have attached a picture of the relay assembly diagram, which I think is where at least some of the problems stem from.

It looks like the small relay on this relay assembly board is a 12v relay, I assume it should be getting around 12v from the transformer to trigger the relay and turn the unit on....It looks like it's a bit low to me, around 11v, As a side note, I also jumped/shorted out the contacts on the relay and I was able to get the unit to turn on with the power button, so something is preventing this relay from changing state......again, any help is appreciated, and I can do more testing and/or checking, with guidance of course...

[budwich]

the diagram shows a 15.7v point that feeds the relay.... what are you reading there and how are you measuring that point?
Also the "5v" point comes off that area too.... what are those measuring? A good chance that the caps (c552) is bad..... maybe.
Can you check that with your meter (cap function).

[eccerr0r]

How are you measuring 11V, 11V is typically sufficient to engage a 12V relay,

Are you getting +5V to the system (J9 pins 1 and 2, or at least +5.6V at the emitter of Q551)?

[thetonywarren]

Ok, so it doesnt look like Im getting the correct voltages at the ribbon cable that should have at least 5 volts, Im not sure which leg of Q551 is the emitter, but I tested at all three legs and none of them are showing around 5.6 volts, they are testing at 2.7v, 2.7v, and 3.4 volts, btw, Im assuming these are DC measurements? not AC voltage? Or am I completely wrong.....

Also, here's a couple of quick videos of what im working with and how Im testing...

https://youtu.be/1BmHXqOzzrg

and

https://youtu.be/MG6TrXVZsWQ

[eccerr0r]

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.

[thetonywarren]

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.......

[lotas]

Is your switch set to 120v correctly?

[thetonywarren]

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

[R_J]

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

[lotas]

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

[thetonywarren]

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

[thetonywarren]

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

[R_J]

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

[lotas]

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

[thetonywarren]

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

[thetonywarren]

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

[R_J]

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

[lotas]

Originally Posted by thetonywarren

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.