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Author Topic: Sankyo 800 start-stop issue...
Burton Sundquist
Master Film Handler

Posts: 302
From: Burnaby, B.C. Canada
Registered: Feb 2017


 - posted July 02, 2018 12:02 AM      Profile for Burton Sundquist   Email Burton Sundquist   Send New Private Message       Edit/Delete Post 
My spare Sankyo 800 has developed a start-stop issue and I was hoping someone more familiar with the electrical side of this model might be able to help. I threaded a 600' reel to view and about 2 minutes in, the motor stopped but everything else stayed powered up ( I quickly disconnected the lamp socket before the film was harmed ). After about 3 minutes the projector resumed playing for about 10 seconds and stopped again. This start-stop cycle repeated for 30 minutes and then resumed playing uninterupted until the end of the reel. I tried it again after having it powered off for a couple of hours and threaded a 400' test reel. The problem repeated on this run too. Any ideas as to the cause of this start-stop issue? any replies will be greatly appreciated.

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Maurice Leakey
Film God

Posts: 5788
From: Bristol. United Kingdom
Registered: Oct 2007


 - posted July 02, 2018 02:30 AM      Profile for Maurice Leakey   Email Maurice Leakey   Send New Private Message       Edit/Delete Post 
The Sankyos are fine projectors, but, unfortunately do have an issue electronically.
The main control knob operates various micro switches, which after many years of use, often fail to make a firm contact. Then it's time for them to be renewed.
This, of course, may not be your particular problem, but it's worth considering.

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Maurice

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted July 02, 2018 05:10 AM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
I am more inclined to thinking this is a motor control circuit board problem rather than a micro-switch problem: it sounds like some electronic components are exhausted (possibly, capacitors?) and can't handle their job properly; in fact the machine works after a long warm up. But people more "electronically-minded" than I should have their say here (Steve Klare?).

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Maurizio

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Steve Klare
Film Guy

Posts: 6916
From: Long Island, NY, USA
Registered: Jun 2003


 - posted July 02, 2018 08:09 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
Thanks Maurizio

(All those years without a girlfriend should count for something!)

Whatever it is it's probably some poor connection that's failing as it heats up. My own first guess was the microswitches, but it could really be many things: for example some poor solder connection on the motor control PCB.

It's probably not a component on the board, usually once they go they stay gone. Then again I've been troubleshooting for three decades now and one thing I know for sure is how dangerous the word "never" is!

The whole thing is figuring out where the voltage stops. If a voltmeter was applied to the circuit before and then after the switches, Burton could either rule them out or pronounce them dead. If there is no voltage there then you move upstream until the voltage shows up. (-or even doesn't)

I had a mechanical engineering professor who said he didn't like working with electricity because he couldn't see it. That's why we need voltmeters!

(-and it's better to see it than feel it!)

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All I ask is a wide screen and a projector to light her by...

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