8mm Forum: Bell 552 Specialist Drive Belt and sound problem

This is topic Bell 552 Specialist Drive Belt and sound problem in forum 16mm Forum at 8mm Forum.

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Posted by Jim Karl (Member # 5446) on October 10, 2016, 09:46 PM:

1st problem, moving selector to FF or Rew does nothing. Looked in back (cover off but activator screw inserted so I can test) and main drive belt seems a little loose. Motor axle spinning but belt is not, until I touch it then it's enough to catch and get going and projector mechanically runs fine in fwd/rew until I stop then same thing when I try to start again. So high tight should this belt be against that brass axle? What size is is and very is a cheap place to find a replacement? Or is there an adjustment that could be done to tighten that I'm not seeing?

If I have to remove it, it looks like a couple of hex screws in the brass piece need to be loosened to slide that piece off correct? I may even need to loosen a piece at the bottom that connects to that geared belt to the left as well.

Problem #2 - No sound. Or rather, no source audio sound, I can hear the amplifier running and the hi/low tone switch is working, just not source audio in the feed. Switch at top of unit is set to sound mode. So my gut was saying preamp stage problem. I have a tube tester and can pull those, check caps for leaks ect but would be helpful if there is a schematic out there for this model. There seems to be a little preamp board of some sort up front as well. I download the service manual and although it didn't have any schematics, it did mention a possible problem in the photocell (being dirty or out of alignment) as a possible cause to no sound but doesn't mention or show where this photocell is located. Any ideas? Liek I said a schematic would be wonderful - then I could inject audio into the amp to narrow down the problem.

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