8mm Forum: Help with Sankyo 800 please

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Posted by Mal Brake (Member # 14) on February 04, 2004, 09:02 AM:

A friend of mine has just bought a Sankyo 800 projector.After 2 minutes of running any film the projector loses the top loop. When the machine is put in to reverse, the bottom loop is also lost.This happens every time the Sankyo is tried. We have eliminated excessive take-up tension as a possible cause but I have absolutely no experience of Sankyo projectors so we are open to any suggestions.
Thanks, Mal

Posted by Mike Peckham (Member # 16) on February 04, 2004, 12:14 PM:

Hello Mal

I've got several Stereo 800s' [and another one on the way] but this is a new on on me. I pressume you are following the correct procedure for threading and the loops start off as they should be?

Otherwise I guess it must be something not doing what it should in the gate area but what I don't know. Have you tried turning it over manually with the inching knob and whatching the claw mechanism with the gate open? On the 800 you can spring it open for cleaning and inspection, you'll get a better view if you pop the lens out.

Sorry can't be of any more assistance but would say that they are great little projectors so well worth getting sorted if you can.

Mike

Posted by Mal Brake (Member # 14) on February 04, 2004, 01:00 PM:

Thanks for the tips, Mike. I haven't seen the projector yet. My friend 'phoned me this afternoon with the problem. He has had other Sankyo projectors in the past and is an experienced projectionist so I assume he is following procedures. The machine was supplied with the instruction book but I don't know how much help that will be.Thanks again Mike
Mal

Posted by James N. Savage 3 (Member # 83) on February 04, 2004, 03:02 PM:

Hi Mal,

I have owned and used Sankyo 800's for most of my hobby since 1980 or so. It sounds like the same problem I had on one of my machines recently. After about a minute or so of running a film, the film would start jumping and when I looked inside, the top loop was gone. This would re-occur over and over.

This is how I resolved the problem (please excuse my ignorance on technical terms, bear with me):

While running a film, as it starts to jump the loop, slightly open the film gate (the part between the bulb and the lense that opens easily that the film goes through). You may notice that the film will ride smoother, but you will lose some of the focus. The loop should hold.

If everything happens as I have stated above, let me know and I will tell you how I resolved the problem with mine.

Nick.

Posted by Kevin Faulkner (Member # 6) on February 04, 2004, 04:01 PM:

Elmos will also do this trick if the claw tip protrudence (?) is not set correctly. It could also be that the gate pressure plate is incorrectly placed or has insufficent pressure.

Kev.

Posted by James N. Savage 3 (Member # 83) on February 04, 2004, 06:55 PM:

In my case, it turned out that there was too much pressure on the film under the pressure plate and some of that pressure had to be relieved to get the film to play smoothly.

Nick.

Posted by Maurizio Di Cintio (Member # 144) on February 07, 2004, 08:44 AM:

I would agree with Kevin's explanation IF, with the term "loss of loop", Mal claims that the upper loop becomes too big and not too small.

If this is actually the case, since I see no way to fix pressure plate's strength without makeshift solutions, the problem lies very likely with a worn out shutter cam and/or worn out claw arm. The latter indeed rests onto the shutter cam by means of a teflon ball, and is held in place by three springs inside the main mechanism. The ball is very hard and if regularly used/lbricated it should last for long, but in the long term it is supposed to wear. Once this happened the claw is no longer free to move upwards before engaging a new hole in the film and this tends to be tranported back(up)wards for a small fraction of time. IN early stages of the problem a visible jitter is to be experienced on the screen, but when it grows worse, the film may literally jump and lose its loops.

If all this is really the case, the only way to solve the problem is to find a new claw (but better replacing the shutter too); even replacement of the teflon ball only will suffice as it can be removed from the claw arm; it shouldn't be difficult to find: some older bottom of the range Yelco's should have a similar mechanism.

I hope your friend can solve this problem. I'd try to do something personally but I live too far away, and shipping the projector would prolly be less than cost effective.

Regards.

Oh, I was forgetting.

THere is a way to temporarily fix the problem: it consists in shifting the whole shutter about 1/2 mm (no more!!) back on the main shaft. There are three headless screws which hold it in place (sorry I don't know their name in English) you'll need a thin "L"-shaped exagonal tool to unscrew them. This is really worth a try.

Posted by Mike Peckham (Member # 16) on February 07, 2004, 09:01 AM:

Maurizio

I think the English words you were looking for might have been 'Allen Bolts' and Allen Keys'? In case it helps at all...

Mike

Posted by Mal Brake (Member # 14) on February 07, 2004, 01:28 PM:

Thanks again for the advice. I still haven't seen the projector. My limited mobility means I need door-to door transport to get to my friend.
Maurizio,the upper loop dosn't get too big it becomes nonexsistent.
Thanks gentlemen
Mal

Posted by Maurizio Di Cintio (Member # 144) on February 08, 2004, 05:07 AM:

Than the claw doesn't actually engage the sprockets: the film is transported only by the rear sprocket wheel.
If it is not a problem of worn out film gate, it might be a problem of claw positioning along the horizontal axis, i.e. the claw engages each hole either too inside or too outside and the film slips from it. Have a loop of (useless) film run through the machine for a 5-6 minutes and then check the sprocket: there might be signs around each hole left by the claw, if it needs registration.
Hope this helps. Good luck.

Posted by Mal Brake (Member # 14) on February 11, 2004, 03:45 AM:

Thanks for the response everyone. I had an email from my friend and it is indeed a problem with the claw. Luckily he has some spare parts so hopefully the Sankyo will be up and running soon.
Thanks again for your input
Mal

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