Canon ImageClass D660 internal blinking l.e.d.

[David Farber]

This Canon ImageClass D660 printer/scanner/fax was subjected to a power
surge. An open neutral line on the customer's street knocked out a lot of
equipment in a lot of homes. I was able to locate the damaged power supply
board by following the fine aroma of charred components. The result of the
damage was that it just needed a few capacitors and a T4A fuse. I powered it
back up and was able to print a test page ok. However, before I proceed
putting this all back together to check everything else, I noticed that
there's an l.e.d. on the system control(?) board which has an amber l.e.d.
that continuously blinks like a turn signal.
http://webpages.charter.net/mrfixiter/Repair/Blinking-led.jpg

Does anyone know if this is normal?

Thanks for your reply.
--
David Farber
Los Osos, CA

[junebug1701]

It's probably a watchdog circuit. Used to indicate proper operation. If it stops blinking, it means the processor is locked up. Perfectly normal.

[David Farber]

Thanks for that explanation. Everything seems to be working fine. I'll
reassemble it and stop worrying about it. :-)

[N_Cook]

I never expected to see a blinking LED inside (nothing seen of them on
the outside) an audio amp. Suspecting it may sometimes be possible to
end up with a clicking sound coming over the audio, via shared ground
routes or whatever - but there are such blinking LEDs in normal operation