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From: rob34 on 5 Feb 2010 06:07
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
From: Mark Zacharias on 5 Feb 2010 08:11
"rob34" <radiorascal34(a)yahoo.com> wrote in message
news:f34cf043-655b-4ed4-9733-2f5ee435592d(a)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.

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