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Martin
Martin, Engineer
Category: Home Theater-Stereo
Satisfied Customers: 4875
Experience:  16 years, include works in aluminium plant, industrial machinery, military weapons, programming
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I have a Pioneer VSX-920-K Audio / Video receiver I use to

Customer Question

I have a Pioneer VSX-920-K Audio / Video receiver I use to connect my high def projector too. Recently the power does not stay on. Essentially, after about 5-6 seconds after turning the receiver power on, i hear an internal click at the rear left of the box and it shuts off. I have unplugged the unit, tried different outlets, etc and nothing gives. I had a similar problem with at TV years ago and it ended up be a bad capacitor, etc. can you help?
Submitted: 1 year ago.
Category: Home Theater-Stereo
Expert:  Steve G. replied 1 year ago.
Hello there and welcome to Just Answer. My name is ***** ***** I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.
Can you disconnect the speaker wires, move them away from the back of the receiver and then turn it on.
Does it stay on or turn off?
Please let me know so that we can continue.
Regards
Steve
Customer: replied 1 year ago.
All wires, hdmi's, have been removed. only cord still attached is power cord
Customer: replied 1 year ago.
Still clicks off after 5 seconds... yet when I change sources from TV/SAT to DVD or HD, the lights come back on, but then turn off again after 5 seconds, but doesn't click again.. just removed text from screen
Expert:  Steve G. replied 1 year ago.
Ok, then a component level diagnosis will be required. That is not something I am capable of over the internet. Most likely you have popped an output transistor but tracking that down is outside the scope of my capabilities.
I am going to opt out of this question which will allow other experts to chime in.
Hold on.
Customer: replied 1 year ago.
can anyone help
Expert:  Martin replied 1 year ago.
Hi. I parsed the service manual and it is not very helpfull without having the unit on my test bench to do test point check.
I notice from research i made that many over ther years got the same problem you have, nobody seem to know the cause(s) that said. The first thing would be to check the power level internally to see it they are OK. Also verify that all internal cables are well seated and same for slotted board if any are present.
Lastly, one of the most common problem i see with amps is a deffect in 1 or more tantalum capacitors that are at the outputs to smooth out the staircase effect created by the digital to analog convertion. Those are usually not needed for test operation (sound may feel a bit more grainy) so removing them can help to pinpoint the problem.
If the problem is just starting, you may try to heat the power supply capacitor with an air dryier (not burn them, just warm them) and then try to power the unit and see if it stay ON longer. If it does, they they could be the suspect (trick don't work with tantalum ones).
You can also visually inspect all components for trace of darkening. I also sometime use a pensil with a plastic tip and press in some places on boards to see if i can make a cracked copper path to connect. Having a spare one to do part swap is also a very fast way to locate a problem.

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