Mark Zacharias wrote:
"Alan Liefting" wrote in message
...
Got a Technics SA-EH600 home theater system with a fault. The display
comes up when first powered up from the mains but when the
power/standby button is pushed it says "GOOD-BYE".

The relay that activates the +/- supplies for the output stage never
activates. Did a basic check for shorts and opens but nothing was was
obvious.

Any ideas?


Alan Liefting


Blown channel. DC offset. Power supply issues. The usual. One can jumper
the power relay contacts and bring the unit up on a variac, then look
for DC offsets or excess current draw. Alternatively, one can use a
double-ended POLARIZED power cord plugged into the switched AC outlet on
the rear, and connect that to the variac. If there is a second switched
outlet on the receiver, plug it's own power cord into that one - this
would ensure that the microprocessor and smaller sub-supplies are
energized.
Might be a good idea to put a smaller main fuse in there or substitute a
100 watt lamp for the fuse. Then if there's a hard short, the lamp will
alert you by glowing bright. A dull glow after initial charging of the
power supply caps is normal.


Mark Z.

If the output stage relay never activates how can the microprocessor
detect any psu issues?

Alan