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Pete, Electronic Engineer
Category: Consumer Electronics
Satisfied Customers: 18108
Experience:  Over 16 years of experience installing and repairing electronics.
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I have the same problem with the model sr5500 but all supply

Customer Question

I have the same problem with the model sr5500 but all supply of + 5V are correct (4,92V), all transistors are in working order (amp). After inserting the cold solder amplifier turning it on but immediately turn on the relay (HEAT) and amplifier working at low voltage. By chance I gave 12V to PA_FAIL signal and amplifier shutdown and now runs with an error CHECK POW5. Could I damage the microprocessor ???
Submitted: 2 years ago.
Category: Consumer Electronics
Expert:  Pete replied 2 years ago.

Hi there,

This is unlikely to be caused by a damaged microprocessor.

"CHECK POW5" usually indicates a blown power supply board.

Try fitting a replacement board and let me know if that resolves the issue.

Customer: replied 2 years ago.
not always CHECK POW 5 indicates an error with voltage, eg: connection POSISTOR of the heatsink also crashes the error
Customer: replied 2 years ago.
sorry releasably POSISTOR also causes this error
Expert:  Pete replied 2 years ago.

Yes, that is correct.

Customer: replied 2 years ago.
I think everything has already checked on the supply boards and I have no idea what to do next
Expert:  Pete replied 2 years ago.

Have you tried fitting a replacement power supply board?

Customer: replied 2 years ago.
I'm sorry but my English is not too good, otherwise you explain what you mean which replacement power supply board?
Expert:  Pete replied 2 years ago.

The power supply board inside the receiver unit needs to be replaced with a new power supply board.

Customer: replied 2 years ago.
if I had a new supply board I would not ask for advice
Expert:  Pete replied 2 years ago.

Ok, then to try repairing the existing board will be very difficult, especially since you have already checked everything and it all seems good.

Swapping in a good board is a very simple and fast way to prove that there is a fault with the existing board.

If you want to try repairing your board, then you are going to have to look at virtually every component and every solder joint, and even the condition of the board itself.

Start by looking for any obvious burned or damaged components, and replace them.

Also touch every solder joint with a soldering iron to reflow the solder joint, in case there are some cold solder joints that are causing the problem.