mid 1980s amplifier. no builtin tuner. the unit is relatively heavy so I
assume it has some good quality stuff inside!
no output volume. unit lights up, gets hot.
I do not know about pre-amp, this is simply a unit which has four input
slots (phono, tuner, cd, aux/vid) and tape deck input/output. there are two
speaker channels A, B each having right and left channel (no surround, no
5.1)
I assume something on the board is broken... there is one interesting
component on the board which sticks up and has a transparent cover,,,it
looks as though it has a copper coil inside. without my giving the part
number of this transparent covered thingy, maybe this thingy is what is
broken! I don't know how to scope anything, nor do I have the tools! but,
if the unit gets hot and does light up, what part of the process can we
assume is working? I notice when switching input selection, sometimes
there's a slight lighting of the volume signal indicator. when the unit was
working fine, the dual channel volume signal indicators would dance
right-to-left with different sound output. I doubt I would pay much to have
the unit professionally serviced, but if I knew which part was broken, I
might buy a replacement part and try installing it myself! thanks for your
ideas!
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?
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. 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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