Sony HT-5500D receiver problems

[rob34]

This unit will come on and the protection display will come on. I have
had the volume turned down and I have checked the speakers for any
problems. I have even checked all the output transistors and various
components around the outputs. Has anyone run into this problem with
this unit? Would anyone have a schematic or service manual that they
could email me? Thanks, Rob

 

[Mark Zacharias]

"rob34" <radiorascal34@yahoo.com> wrote in message
news:f34cf043-655b-4ed4-9733-2f5ee435592d@m31g2000yqb.googlegroups.com...

This unit will come on and the protection display will come on. I have
had the volume turned down and I have checked the speakers for any
problems. I have even checked all the output transistors and various
components around the outputs. Has anyone run into this problem with
this unit? Would anyone have a schematic or service manual that they
could email me? Thanks, Rob

The receiver portion of this system is the STR-K840P.

If the outputs are OK, the most likely culprit is IC501, an STK350-230.
You should measure DC with respect to ground from the center of each emitter
resistor to confirm a DC offset. Most of the amp channels use UPC series
drivers which are quite reliable, the one channel using the STK is a
frequent offender. Sony won't allow me to distribute their service
literature.

Mark Z.