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Any ideas?

petas

Jan 9, 2013
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Jan 9, 2013
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Hello Guys
I am currently trying to repair a SONY STR-DE597 6.1 receiver, which does the following trouble:
All of it's channels work, but with strong differences in output gain...
when i generate the test tone white noise, from what i hear:
surround BACK = 100%
CENTER = 100%
Front Left = 35%
front right = 20%
Surround Left = 45%
Surround Right = 100 %
the SUB output works OK

is it right to assume that if any output transistors were blown, nothing would be heard from those channels? (MN2488 and MP1620)

Each channel has 4 output transistors and i have all identified them... each channel has the same set. Would it be logical to remove a set from say, the surround right channel (which works 100%) and exchange the set with one of the lower output channels (like front right), to see if the problem follows the transistor set? (or maybe i should only move the two MN2488 and MP1620??)

I don't have signal tracing equipment available, so i am just looking for a way to save this one before ordering transistors or putting the amp to the trash...

i have done a factory reset on it, with no change.

can anyone suggest where else to look for such a problem??

THANKS, any suggestions are welcome.

Pierre D
 

shrtrnd

Jan 15, 2010
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I'm not familiar with your specific amp.
If the selection switches are mechanical, I'd check them pretty closely.
Often with mechanical selection switches for the different channels, the switches
need to be cleaned if possible, or replaced.
If your unit is electronically controlled, I'm barking up the wrong tree.
That's my suggestion.
 

Harald Kapp

Moderator
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Nov 17, 2011
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i have done a factory reset on it, with no change.

Have you looked at the surround preset of the amplifier after the reset? Are all channels set to 0dB? This behaviour could also be the result of some quirky setting by the previous user of the amp.
 
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