8mm Forum: GS1200 Auto Threading Depress Lever woes

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Posted by Xander van der Merwe (Member # 125) on January 18, 2004, 02:30 PM:

I'm having troubles with the auto threading depress lever not releasing. It does not seem to make a difference whether the takeup reel automatically winds the film up or whether you have to do it manually. It does sound like the micro-switch under the takeup film makes contact (I can hear the click) but the lever just doesn't release and the light doesn't come on as a consequence. Stopping it and turning the takeup reel clockwise a few times to activate the switch doesn't help either. The only way I can get it to work is to randomly forward, stop, reverse, forward, etc until I get lucky. Last night it took me about 5 minutes before I got lucky...

Any ideas? Is this a common problem? Is it likely to be the switch or the lever mechanism itself? Any pointers as to how to try and solve this? I had the whole machine serviced about a month ago.

TIA

Posted by Ugo Grassi (Member # 139) on January 18, 2004, 05:02 PM:

Probably the micro contacts of the switch are burning out. You have to disassemble the micro switch. It's not difficult. Do you have the service manual? Anyway, before to disassemble it, try to clean it with a spray for electric contacts.

Look here...
ftp://ftp.filmshooting.com/upload/servicemanuals/

it's a zipped file.

When you disassemble the switch, before to change it, test it! You have to close the contact with something of metal.
Some little suggests to disassemble the frontal lid (that one with the VU-Met).
Open the posterior lid; in corrispondence of two corners of the frontal lid there two screws (unscrew). Now, looking the frontal lid, under the main switch (stereo, mono ect.) there is an other screw. When you remove the lid, be careful because there is a cable (with a socket) which connects the vu_meter to a board.

Posted by Xander van der Merwe (Member # 125) on January 18, 2004, 05:25 PM:

Thank you Ugo for both the tip about the switch and the link to the service manual. I will start with the switch.

Posted by Kevin Faulkner (Member # 6) on January 21, 2004, 04:39 AM:

Hi Xander,
As Ugo says it will be the microswitch. The contacts get dirty and only partially make contact. In my experiance I would not bother to try cleaning the switch but replace it with a new one. It resides in the back behind and to the left bottom of the top sprockets drive cog. Its a bit of a devil to get out but you should be able to manage it.
Any small microswithch will work. They are at least standard in their layout and size.
Had to replace one this weekend for exactly the same reason.

Kev.

Posted by Xander van der Merwe (Member # 125) on January 21, 2004, 01:43 PM:

Thanks guys. I successfully replaced it last night with a similar one from my local electronics store. It was interesting to me that when testing the old switch with a multimeter it appeared to be ok. Anyway, all is well again and working like a new one [Big Grin]

.

I discovered that my GS1200 is dated as 21 Nov 1979. I imagine this would be one of the latest models?

Posted by Kevin Faulkner (Member # 6) on January 22, 2004, 06:26 AM:

Where did you find this date Xander? If its the one printed on the main motor then this only refers to the date the motor was made. Elmo seemed to have big batches of these motors made so the date doesnt really tell you when the machine was made. Its also possible that the motor had been changed at some point if it had failed.
Does it have the lines on the vol controls and the rear facing loop restore lever?

Kev.

Posted by Xander van der Merwe (Member # 125) on January 22, 2004, 01:43 PM:

Yes, the date was on the motor and it does have the rear facing loop lever and lines on the control knobs. I was under the impression (incorrectly so?) that the motor date implied the projector date?

Posted by Tony Milman (Member # 7) on January 22, 2004, 02:04 PM:

Xander,

I think that this is a very strong indication of machine age and the fact it is a series 3 makes it all the more likely. Give or take a couple of years.

Are you enjoying it? I was most impressed by your pictures of the cinema you have set up. Such an understanding partner you must have!!!

Tonyb [Wink]

Posted by Mike Peckham (Member # 16) on January 22, 2004, 03:11 PM:

I think it might be interesting to look at a few serial numbers and see if there's a discernable pattern [ok I know that sounds really sad [Roll Eyes]

] but I wonder if there will be for instance an indicator in the serial number that refers to date of manufacture, version and type ect?

Here are my two for starters;

Serial no: 825756 Version 1 originally sold 12/11/79 [thats 12 November UK style [Razz]

].

Serial no: 825292 Version 1 Motor date July '79

Mike.

Posted by Kevin Faulkner (Member # 6) on January 22, 2004, 06:39 PM:

I can feel this one turning into a very long thread. It now looks like there is a Ver 1.5 GS and not just the 3 vers. I have now seen 3 GS's in week which have the take up motor control board but with the fixed non switched front input roller. This vers has only 2 poteniometrs on the control board. Interesting, as they obviously knew that the mod needed to be done but probably waited till they ran their stock of older sprocket guides down. The 2 pot control board has the place for the 3 pots but the third podition is not drilled out.
We live and learn.
Kev. [Smile]

Posted by Xander van der Merwe (Member # 125) on January 23, 2004, 05:06 PM:

My serial number is 828363 with rear facing loop lever and lines on controls.

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