Help with I Robot Switching supply

Help me folks! :( I know I should just install a modern switcher, but I
wanted to try and keep this machine original. Here is the mess i'm into.

Original IR switching supply. One component that I can't seem to track down
makes a nice squealing noise on power up. About 10-20 seconds later
(sometimes longer) the machine shuts down and the LED comes on.

I've replaced the switching transistors and all electrolytic caps, except
for the 2 large ones (on order). I replaced these parts last week with no
help.

Today I got some parts in from Mouser, installed them and blew one of the
audio amps in half. Here is what I ordered and then what was original.

CR10-11 was 5A 150V Fast Recovery Diode. I installed 5A 200V Super Fast
Rectifier. Mouser part 583-SF54

BR4 12A 150V Fast Recovery Rectifier was originally a FEN16C, I installed
from Mouser a 16A 200V Super Fast Rectifier, Mouser part 583-SF164C

Also I changed (4) 1n4947's, Mouser sent (4) 1n4948's. They crossed to me,
so I replaced em.

I'm not great by any stretch at troubleshooting this stuff. Did I replace a
part with a wrong one? Or did the new parts finally destroy (audio amp) the
weakend part?

Can a simple audio amp shut down one of these switchers?

Thanks guys, I really need some help with this one.

Steve Zeuner

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Received on Fri Jun 02 13:49:02 2000