"Alec S." wrote in message ...
Hi,

I'm repairing my flatbed scanner but I can't figure out what the output
pin of
the 7905 connects to.

Here's some snaps:

Front: http://img517.imageshack.us/img517/9646/23249045py3.jpg
Back: http://img524.imageshack.us/img524/84/13459958xc0.jpg
Reverse: http://img524.imageshack.us/img524/7761/30152421ct5.jpg

I can see where the input voltage and ground pins lead, but the output pin
doesn
't seem to lead anywhere. Is it a layered PCB or am I missing something?

It makes sense that the output voltage isn't connected because the scanner
does
nothing when plugged in; the power LED doesn't even light.


--
Alec S.
news/alec-synetech/cjb/net



That would be a 7 *8* 05 then ... Just a comment as the pinning is different
between a 78 and a 79. The board has a t least two layers as evidenced by
the nearby vias. Is there actually any voltage appearing on the output pin ?
If not, is there voltage on the input pin. If there is, is the device
getting hot ? There should be an output decoupling cap nearby - probably
around 1 to 10 uF - with possibly a 0.1uF across it. You should be able to
follow the print from those. It should be easy enough to 'pick up the trail'
from the 78's output pin with your multimeter set to ohms, anyway.

Arfa