Sony STR-DE525 faults to Protector mode

[Gary L. Woodruff]

Howdy, I have a Sony STR-DE525 that faults to protector mode when turned
on. I have located a2 blown output transistors and a burnt resistor
(R527). I have a print and have verified the two large caps or good. I
would greatly appreciate any tips as to other components to check before
ordering replacement parts. Any and all help is greatly appreciated.

thanks, Gary

 

[Mark D. Zacharias]

Howdy, I have a Sony STR-DE525 that faults to protector mode when turned
on. I have located a2 blown output transistors and a burnt resistor
(R527). I have a print and have verified the two large caps or good. I
would greatly appreciate any tips as to other components to check before
ordering replacement parts. Any and all help is greatly appreciated.

thanks, Gary

Don't have the schem handy, so the resistor number doesn't work for me right
now.

Generally speaking, you are good to just replace the outputs, check /
replace resistors associated with the bases of the outputs, that is 4.7
ohms, 10 ohms, 180 ohms, whatever. Also the white emitter resistor, usually
..22 ohms at 5 watts dual package. Also check the bias transistor mounted
against or under the heatsink, and other small transistors in the general
area. 2SA988's for example.

Mark Z.