Most of the time, when the receiver is powered up, and after a few seconds, there will be a loud hum and POP from the speakers, the PROTECTOR display will flash. This does not happen every time the unit is powered up, but more than half of the time. If I shut down the unit , wait a couple of minutes...the receiver may power up OK , or may pop and go into PROTECTOR mode again. So far, no fuses have blown. In order to avoid the problem, I've resorted to keeping the receiver powered up 24/7. Until recently, this receiver has performed flawlessly since purchased in 1999, and I really like it, so, would like to keep it operational. I am a ham radio operator and hold a commercial radiotelephone license, I have no problem doing the repair, but, help with diagnosis will be appreciated. Ted Brough

Hi Ted,

First of all, thank you for posting your question here at Fixya.com.

"Protector/Protect" is an error code for out-of-regulation condition either on the power supply board and/or on the Sound output circuitry.
I've encountered this kind of symptoms not only on Sony home audio sound system but in almost known brands and the faulty parts are the same >>>> smoothing/filter electrolytic capacitor.
This is very common most especially on older unit because the capacitor begin to dried up resulting to voltage/audio out-of-regulation. In the first stage of fault, warm up will make itself stable but it will get worst as times goes by.
This is fixable and not a costly repair because this is one of the cheapest part on the board and widely available at electronics supply and online. You must have a test instrument (capacitor checker/tester) because not all capacitor that are look physically fine is in good condition, capacitor checker will reveal its condition.
Watch the video below for more info regarding electrolytic capacitor.




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For efficient troubleshooting, you must know which section/board are going to repair. In your case, AC board, DC board, REAR-AMP board, and the mainboard(Sound output circuitry) are going to troubleshoot.






> Check or replaced C905 on AC board - this board is where the AC power cord's directly connected.
> Check or replaced C801, C803, C804, C807, C808, C809 on DC board - this board is where the two larges electrolytic capacitor is located.
> Check all electrolytic capacitor on REAR AMP board most especially in front of IC701(UPC2581V)
> Check the electrolytic capacitor in front and at the back of IC501 and IC601 (both UPC2581V) on the mainboard.

Note : IC501, IC601, IC701 are mounted on aluminum heat sink. Concentrate first on AC and DC board.

Once you've isolated the faulty electrolytic capacitor, your unit will back to normal again.

Hope I helped you.
Rating and feedback are highly appreciated.
Have a nice day! Good luck and take care!

Kind Regards,
Jdvillanueva