Sony STR-D915

[loopyloo]

Has anyone worked on one of these ?
It appears the center channel isn't working.

[loopyloo]

This unit has several switchable modes for the speakers. 2 channel, 3 channel (which is LF, RF and centre), 5 channel and 5 channel wide.
After having another look, I find that the Left Front channel is also faulty and only works in 2channel mode and is about a third the volume of the right front.
The centre channel doesn't work at all.

Finals test ok with a meter and so do their emitter resistors.

[loopyloo]

Anyone ?

[Skepticist]

Not familiar with the model but I'd approach it by checking power supplies first, then check for signal on the output(s) of the pre-amp/processing stages and that should eliminate most of the possibilities fairly quickly. Directly injecting a signal into the output stages easily verifies whether they're functioning or not before you start removing components.

[Skepticist]

Just a thought but how is that centre channel derived?
If it's a difference between left and right inputs and those are bridged for mono output there'd be no difference to amplify there for example.