60 cycle hum in a 8 mm projector

[Wes]

Guy at work that is into old movies on film asked me about hum in a movie projector and
how to cure it.

I'm assuming that the filter capacitor(s) in the power supply is the issue but then I
don't play with audio much.

Any tips on troubleshooting? It uses transistors, no tubes.

Thanks,

Wes

 

[Tom Biasi]

"Wes" <clutch@lycos.com> wrote in message
news:rSoKl.250653$UR4.233721@en-nntp-09.dc1.easynews.com...

Guy at work that is into old movies on film asked me about hum in a movie
projector and
how to cure it.

I'm assuming that the filter capacitor(s) in the power supply is the issue
but then I
don't play with audio much.

Any tips on troubleshooting? It uses transistors, no tubes.

Thanks,

Wes

Hi Wes,
Lets bring your post up to rec.antiques.radio+phono.

Tom

 

[Michael A. Terrell]

Wes wrote:

Guy at work that is into old movies on film asked me about hum in a movie projector and
how to cure it.

I'm assuming that the filter capacitor(s) in the power supply is the issue but then I
don't play with audio much.

Any tips on troubleshooting? It uses transistors, no tubes.

If it uses an optical track make sure no room light is reaching the
photoiode. If you have a scope, look at the voltage feeding the exciter
lamp. They are either DC, or above 20 KHz. Any ripple on that supply
will be detected and amplified.


--
You can't have a sense of humor, if you have no sense!

 

[Wes]

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote:

Any tips on troubleshooting? It uses transistors, no tubes.


If it uses an optical track make sure no room light is reaching the
photoiode. If you have a scope, look at the voltage feeding the exciter
lamp. They are either DC, or above 20 KHz. Any ripple on that supply
will be detected and amplified.

Thanks Mike. Tom, I can't reply to your suggestion since agent won't download your
message. Something with easy news. I'll keep your newsgroup suggestion in mind though.
Since the guy at work hasn't contacted me, I'm assuming he may not have bought it.

Thanks all,

Wes