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Old 19th May 2019, 4:00 pm   #17
af024
Heptode
 
Join Date: Jan 2003
Location: Ashby-de-la-Zouch (it's not by the sea)
Posts: 853
Default Re: Bell and Howell TQII 1652 16mm projector

Thank you for you further comments.

I suspect that you are correct David - a shorted transistor. It's an amazingly small module. Goodness knows what's in it.

As for the reference circuit, well I think it's ok. At least I'm getting a change on voltage at pin 5 when I switch from 18 fps to 24 fps - not much though - only 0.4 Vd.c. This might be ok?

For completeness:-

U1/EXC-030/XU1 d.c. voltages (projector running, everything connected as it should be):-

Pin Volts
1 39.2
2 15.3
3 0.7
4 0
5 10.8 at 18 fps, 10.4 at 24 fps
6 9
7 9

Regards,

Andy
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