On Mon, 09 Jun 2008 17:08:44 GMT, James Sweet
wrote:


Father Guido wrote:
Hi,

I have a Royal 80MX paper shredder that won't shred (go forward), it
goes backwards fine so the motor etc. are working OK. This just
happened suddenly last week. It's as if the paper detection circuit
doesn't recognize paper being inserted. I took it apart and their is a
small plug in connector on the main circuit board with 4 wires leading
to a small trianglular shaped component (numbered only 0321, which may
be a date code for all I know) with two wires going to each of what
looks like 2 small blue plastic lenses. I assume that when paper is
inserted a circuit (of light?) is broken telling the machine to turn
on and shred in automatic mode. I found nothing on the other side of
the paper entrance, so maybe it bounces light off of the chromed
roller. Anyway, getting a replacement part will be impossible, but...
if I knew how this actually worked I could maybe short out the sockets
on the main board to make it think/detect there is always paper in it
so it would always work, then I could just turn it off to stop it, and
turn it on when I wanted to shred.

Any thoughts?

TIA!

Norm


It's a reflective optical sensor. Nothing more than an infra-red LED and
a photodiode or phototransistor. If you have a CCD camera (webcam,
camcorder, etc) you should be able to see the IR from the LED if it's
working. Shorting across the phototransistor should activate the motor.

I hooked up the paper sensor again and looked at it thru my camera, I
can definitely see the I-R LED lighting up. So, I tried shorting the
opposite pair to the side that I thought lit up, but nothing happened.
Since I had nothing to lose I shorted the other pair, BINGO, the
shredder works in AUTO (as if manual FWD) and REV, but not automatic,
and the cutters don't run continuously either in any switch position.
So I have all manual control, FWD, OFF, REV. Ceh la vie, at least it's
useable this way. Thanks for everyones help!

It may not be the sensor though, sometimes reverse is accomplished
entirely through the mechanical switch, while forward is triggered by
the electronics. Watch your fingers while working on these things.