Lubrication for GS1200

[Clive Carmock]

I have a GS1200 non Xenon machine that runs well, but after a while running it will start to make a noise as if it is running harder, it makes a sort of quiet grinding noise. I have found that a quick stray of WD40 in the area of the claw mechanism makes the noise stop.

Of course WD40 isn't really for lubrication, and eventually dries out and the problem returns.

I don't want to run the machine long like this as I am concerned about damage. I wondered if anyone has any guidance on lubrication of this area of the machine?

[Desmond Godwin]

Hello Clive,
Sorry to hear you having an issue with your GS1200. I can share with you a somewhat similar issue with one of my GS1200. Firstly I assume that the projector is actually able to run film,without any on screen problems? Anyway, I was aware of a rough grating noise that appeared to be coming from the
cam/claw assembly. After a few checks and some head scratching I discovered the noise was actually coming from the main drive motor's belt, and appeared to be resonating off the claw assembly pulley! The projector is 38 yrs old and has had reasonable use. I never had an issue with this belt, but I suppose over time it had become brittle. So to make a long story longer the noise disappeared when I replaced the belt. When you spray WD40 into the claw mechanism
(BTW not a good idea) you make things more slippy and this can take some load off the drive belt -hence the noise stops.
Like within the claw assembly there is not a lot that could make a grinding noise. But that's not to say the cam/claw pulley grease may have dried up.
Something broken in here would interfere with normal film projection - like excessive wear on the claw's nylon bushing, but I'm going on the assumption
that film projection is good.
I attach some pics and service info for you. If you suspect the cam pulley needs lube, maybe try a graphite (high melt point) grease. Sometimes called
molybdenum disulfide (I think that's how you spell it). eBay has seller who appears to have original grease for the GS1200?
When the belt is off the drive motor give it a spin to make sure that it runs without abnormal noise. Hope this might help you somewhat.
Desmond.
P.S Only found out that pics can't be directly posted here, so I only have Vimeo, so I D/L the pictures @ this link (been away for a while)

[Clive Carmock]

Hi Desmond. Yes this GS1200 can run film perfectly. It did have a problem with constantly blowing fuses and the motor not running - this was found to be faulty components on the motor control board. I replaced these and diodes onthe main board together with a power transitisor, and this fixed the issue. Since then it has run reliably.

The grinding noise seems to start a while after the projector is running, and makes it sound like it is working hard to run. When it is cold I don't notice the problem. It projects film perfectly.

I will try replacing the drive belt to see if that helps. As you say maybe even though it appears OK, it might have become a little brittle. This is an early (Mk1?) version machine with a date label on the motor of '78

Thank you for putting the sequence together for me - really useful I will try to obtain the correct grease.

[Clive Carmock]

I've started to work on this machine now. There seems to be a reasonable amount of intact grease in the claw cam area. It hasn't gone hard. I did find some quite sticky grease on the brass worm gear between the two nylon sproket gears. Some of this had solidified. I've sent an hour or so cleaning off as much of that as I can, though have more work to do to clean up that gear. Is there any recommended grease for that area? all of the white plastic gears are in tact with no signs of wear or cracking.

[Nantawat Kittiwarakul]

For light to moderate lubrication Super Lube grease seems to be ok (at least for me) as it doesn't eat away plastic parts and stay stick to the surface quite decently.