In article csY4d.108090$D%.39273@attbi_s51, jay heldman
wrote:
Thanks for the idea of a blown fuse. Not the cause. there's one fuse
inside the unit. it looks good. the unit lights up and gets hot. just no
output. elsewhere online I saw an idea of a faulty "main amplifier IC"
but when looking at this unit, I see two identical ICs with many legs
mounted on the floor plane...I assume one is for each channel...since my
problem affects both channels, I do not believe one of those ICs is the
problem. any other ideas?!!
Is this an integrated amp? Some have main-out/pre-in jacks on the
back that use little wire jumpers to connect the pre-amp to the
power amp. Make sure that those are in place if you need them.
Also, check over all the possible switches that would affect this,
like tape monitor and effects loop switches.
If you have another amp, connect the tape out, and later, the pre-out
to an aux input on a known good system. Then connect a tuner, tape,
or cd to your bad amp. See if you get output at the pre-amp level.
Next, try this in reverse. Connect a device with a variable output
level to the main-in on your SA-930. Make sure the output level is
at zero when you start. Gradually turn up the output level. If
you get nothing out of the speakers, then your amp really is bad.
A common problem with power amps is the shutdown circuit. If it
has a relay, check it to see if it is bad. Look for additional
fuses. Check to make sure there are no wire fragments or metalic
dust that is shorting out the wiring, the speaker connectors, or
the circuit board. Finally, look for any variable controls on
the circuit board. You may have some DC voltage making it to the
the speaker outputs. One of these controls might be able to adjust
the DC offset to fix that (you likely need a service manaul to
know how to adjust it).
Beyond that, you need a scope to start tracing out the audio
path to see where your sound is getting lost.
-john-
--
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John A. Weeks III 952-432-2708
Newave Communications http://www.johnweeks.com
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