Chinon 2500 GL questions and issues....

[Philip Hamilton]

So if you look at the image above I think I have isolated the issue. When the drive wheel is in the position marked by the RED arrow then the mechanism attached to the spring right in front of the motor wheel is in a position where there is maximum pull on the spring, then if you engage in forward F - the motor turns but it cannot get the drive wheel to turn. The belt will slip.

If I give the wheel a slight turn forward - past the point where the spring is tight then the forward engagement works fine. It will only happened if the wheels are in this position when you stop the motor. It's like a roulette wheel!

I have never seen this to be an issue in Reverse-R because I think the torque is different because of the reversed direction of the spin. I have cleaned the white plastic wheel with alcohol and cleaned off the belt - a brand new belt I might add.

Seems that the belt is tad to big - if it were tighter I think it wouldn't slip. But it was purchased as 'NEW". Same size as the belt I removed. I also though that if you put some sticky substance on the wheel - the belt would grab it better - but I don't think it was designed this way.

Anyway, looking for ideas here. Thanks again in advance for chiming in.....

[Dominique De Bast]

Philip, just be sure and to eliminate one of the possible sources of the problem, did you order a belt referenced for your projector (same model) or did you measure the one that was already there and ordered the same ? It already happened to me that the belt that was on a projector was not the correct one.

[Philip Hamilton]

Dominique - Yes! I ordered it for the Chinon 2500 GL. I compared it to the belt I took off (that I suspected was stretched) and it was the same size. So I suspect it is indeed a belt meant for the Chinon 2500. Could I have been sold a 'stretched' belt? I guess. No way to tell unless I order yet another one to see if it would work. I would think though that the slippage would occur more often and with the wheel in different positions --if it were the belt. Only when the wheels are in the position in the PHOTO I posted, and only then. Weird.

[Dominique De Bast]

Hope some member can tell us what is exactly happening to your projector.

[Philip Hamilton]

Hope some member can tell us what is exactly happening to your projector.

So.....as a long shot - I travelled over to the Camera and Repair shop where I purchased my first 8mm projector - it was an Argus in 1971. I loved that shop because they had all the cool 8mm movie digests of my favorite horror films.

Anyway, I brought with me the belt I took off of the Chinon that wasn't working. It is exactly like the new belt I ordered for $7.95 - same size etc. As you know it has the same problem.

Well they had a box of old and some new projector belts - AKA Box O' Belts. I found some that looked exactly like the Chinon but they appeared used. Then I found one that was round - no stretching - a bit thicker and stronger than the Chinon belt but at the same time VERY close. I paid them $5 for it.

Got home and installed it. I was worried it might come off the pulleys but it doesn't. It works fine. I position the wheel where it fails on the other two belts. Boom! It works. I can't seem to make it slip now. So definitely a stronger belt seems to have fixed the issue.

But that makes me wonder why the so-callled new belt would not work. Different rubber? more stretchiness? Not sure. But this rogue belt seems to be doing the job for now.

And, yes, I am going to go with Janice's suggestion of a Sankyo 2000H. I will sell this one on eBay. Thanks!

[Nantawat Kittiwarakul]

That "genuine" replacement belt is, to be honest, visually identical to a generic o-ring that can be found from most hardware source.

Generally there's nothing wrong with this as long as it works. However in this case this "belt" seems just a tad too thin, making it resting at the bottom end of the pulley groove rather than riding on the sides of it. No wonder why it can't overcome the initial torque of the drive cam. This also explain why the thicker replacement belt works right away.

My solution - buying bulk loads of assorted o-rings from hardware store (I currently have about 20-30 of them in storage). Even none of them fits perfectly but you'll at least have the closest approximation to begin with.