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Old September 21st 07, 03:52 AM posted to rec.photo.equipment.medium-format
viewerofrecphoto
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Posts: 19
Default Microtek 120TF Scanner - no support

On Sep 18, 10:25 am, viewerofrecphoto wrote:
On Sep 18, 10:01 am, "Neil Gould" wrote:



Recently, viewerofrecphoto posted:


On Sep 18, 8:09 am, "Neil Gould" wrote:


Sorry to hear that the easy solution wasn't the fix.


If I follow what you've described, that it works soon after you turn
the unit on, but soon stops working, it sounds as if there is a bad
capacitor in the lamp's trigger voltage circuit.


There are 2 caps on the driver board - one connects to the lamp output
and the transformer. Its labeled "1S 3KV SEC:". The "S" might be an
"8"


This is a likely culprit. The key is the "...3KV...", or 3,000 volt
rating. All of the lamps had a trigger voltage higher than a couple
hundred volts, and it is typical that a capacitor such as this one would
feed a coil that connects to the lamp (you may be mistaking the coil for a
tranformer?). I'd replace this cap and see what happens.


The other cap is near the input, between ground and +12V and is
labeled
".47uf 50V"


I doubt that this cap would affect the problem at hand, but while you're
in there, replace it, too.


Neil


i just ordered from Mouser. will report back...


The new capacitor is in. So far, I've scanned a couple of slides and a
couple of
negatives and it seems to be working. This is using the new bulb and
the scans
look fine, with no recalibration other than what Lasersoft does
automatically.
I also replaced the noisy fan, so I'm very happy.

Thanks for your help!