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