8mm Forum: GS1200 Take up Reel problems....

This is topic GS1200 Take up Reel problems.... in forum 8mm Forum at 8mm Forum.

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Posted by Alan Rik (Member # 73) on September 22, 2005, 08:45 PM:

Ok. It was bound to happen. My GS needs some tinkering. I noticed when rerecording Toy Story Audio the Take up reel which was doing fine the first 400ft (Toy story mounted on 2x800ft reels) started to move very slowly after that. By the time it got to the end of the 800fter it was almost not moving. I could easily stop it with one finger. Does anyone know how to adjust the torque on the take up motor or should I be looking in another direction?

Posted by Ugo Grassi (Member # 139) on September 23, 2005, 01:47 AM:

Look near the front arm motor. There is a little board with three trimmers. It's the first or the second. If this way doesn't fix the problem, I have a bad news for you. The problem comes from the big relay on the main board. It's necessary to change it. I can explain how to do it (there is a topic in this forum on this argument), or I can do it for you...(you pay only the shipping cost and the spare parts) [Wink]

Of course you have to disassemble the main board from the GS (it's easy...) to send it separatly.

Posted by Alan Rik (Member # 73) on September 23, 2005, 07:11 AM:

Hi Ugo,
Thanks for the reply! Can you post some pictures of the switches on the motor? I couldn't find them. Also thanks for the offer. Lets hope that it doesn't get to that!

Posted by Ugo Grassi (Member # 139) on September 23, 2005, 10:59 AM:

If you don't see the little board with three trimmers, it means you have a ver. I.
The service manual says: If insufficient torque, change the position of wire from the 3v to the terminal 4v on the transformer. Look the transformer: there two sockets with the number 3 and 4. If the 3 is connected, the 4 is free. If the 4 is connected.. you have the problem on the main board.

[ September 23, 2005, 01:25 PM: Message edited by: Ugo Grassi ]

Posted by Mark Norton (Member # 165) on September 23, 2005, 02:55 PM:

I've had this same problem on my GS1200 and it was the relays on the take up/rewind curcuit that needed changing. Could it be a common problem due to age?

Posted by John Cook (Member # 203) on September 23, 2005, 05:45 PM:

A relay problem? Has anyone disassembled their relay after removal, if this is in fact the problem the relay contact surfaces must be pitting and or covered with carbon from arcing during open/closure.

Since his motor was turning although slowly we do know that the solenoid was working only the contacts were presenting a higher resistance to current flow.

I wonder if they can be disassembled and cleaned, or worst case buffed?

Regards, John

Posted by Ugo Grassi (Member # 139) on September 23, 2005, 05:52 PM:

I did it, but it's hard to clean the contacts, and the result isn't reliable. I cleaned the contact on the GS I sold to Jean Marc (and that machine had few working hours behind) and when the GS arrived to France... the take up reels fineshed to work!!
I sent to Jean Marc a whole new main board, and when I get back that one defective I changed the relays.

Posted by John Cook (Member # 203) on September 23, 2005, 05:59 PM:

Ugo,

Are the relays in a removable socket(bend back a wire retainer clasp and pull the relay out of the socket) or did you have to suck the solder from the printed circuit board's (PCB) pads in order to remove the relay from the board?

I have to admit I haven't had my GS1200 open yet for any problems, running on borrowed time.

John

Posted by Alan Rik (Member # 73) on September 23, 2005, 08:51 PM:

I adjusted the take up reel trim adjustment and it worked a little bit better but I can still stop the reel from turning with my hand. It must be something else. Ok Ugo...how should I go about doing the relay? I have to say I saw the pictures from an earlier post and I was scared...!!!

Posted by Ugo Grassi (Member # 139) on September 24, 2005, 03:17 AM:

quote:
but I can still stop the reel from turning with my hand.

This is not a test. Is your GS able now to take up the whole 800ft spool?

Posted by Alan Rik (Member # 73) on September 24, 2005, 08:10 AM:

Yes, there is not much torque but it can take a full 1200ft spool without stopping. Am I crazy? Are all GS's this way? I dont remember ever having a problem with my other ones...

Posted by Ugo Grassi (Member # 139) on September 24, 2005, 09:48 AM:

Oh no! you are not a crazy. I can never say so! Not I! [Big Grin]

Are you able to measure the voltage supply to the motor? Follow the blue and read cable from the motor to the little board, and measure there the vultage. Let me know..

[ September 25, 2005, 05:10 PM: Message edited by: Ugo Grassi ]

Posted by Mark Norton (Member # 165) on September 25, 2005, 05:47 AM:

As I remember you can test the supply voltage at either motor as they are both on the same curcuit. The supply voltage in FWD should be near 3 volts D.C. and it should be the same in reverse projection. If you have the full 3 volts in reverse projection (Not rewind of course) but a voltage drop in FWD projection, (at 1.5 volts the take up reel barley turns), accross the two motors then this would be the same problem I had.
Now I had a well known Elmo specialist replace the relays in mine.

Posted by Kevin Faulkner (Member # 6) on September 25, 2005, 09:07 AM:

The relays will cause the motors to work, not work or be intermittant. In forwards projection the voltage accross the two motors is in the order of 5.5V (top pot). In reverse projection its about 6V (middle pot) and if the little switch/roller at the film input is activated the voltage should drop to about 5V (bottom pot), if the machine has this facility built in. These voltages are a good setup guide. Voltages are recorded without a load on the motors.
The voltages in the service manual are only good for the ver 1 machines with out the control board next the the rewind motor. With these early machines the voltages were controlled by using differennt tappings on the main transformer. When Elmo introduced the control board they also changed the voltage spec of the motors which means that the 2 versions of motor shouldnt really be swapped otherwsie the torque wont be correct.
Using the above voltages is the way I normally set these machines up. If this doesnt give enough torque then its quite possible that the problem is due to worn brushes or very dirty armatures within the motors. These motors can be stripped down very easily and given a good clean. Its important to make sure that there are no carbon deposits between the armature contact segments.

Kev.

Posted by Colin Preston (Member # 68) on September 25, 2005, 04:47 PM:

I think that Kev is spot on there. I don't know if you chaps recall, but I had the same problem with my GS. Afetr trying lots of things, I ended up having the motor replaced and it has been fine since [Smile]

(Touch wood)
Col

Posted by Alan Rik (Member # 73) on September 26, 2005, 11:10 PM:

Ok. I took out the trusty multimeter and it read as follows. The top setting turned out to be 3.75 volts and the middle one read 7 volts! By trying to adjust the top pot I could only make it go lower to 3 volts..but I could never get it to 5.5. So....now what? Do I have to take the motor apart? Sigh...

Posted by Ugo Grassi (Member # 139) on September 27, 2005, 02:00 AM:

The carbon on the main relay is the caused by the spark product by the electricity when it starts to cross the contacts.
This carbon can interrupt the crossing of electricity, but can also to make a resistance.
If you are sure to the take up reel motor only 3/4 volt arrive, it means the motor is ok and there is a good chance the problem is on the main relays.
If you want I can fix your problem. To disassemble the main board is easy (ask to Jean - Marc..).
Send me a mail if you like...

[ September 27, 2005, 04:57 AM: Message edited by: Ugo Grassi ]

Posted by Kevin Faulkner (Member # 6) on September 27, 2005, 11:10 AM:

Alan, Does the board have the 2 or 3 pots?

Kev.

Posted by Alan Rik (Member # 73) on September 27, 2005, 11:17 AM:

3 pots.

Posted by Ugo Grassi (Member # 139) on September 27, 2005, 04:52 PM:

John, excuse I didn't see your question.
The original relays are soldered on the board. [Frown]

Posted by John Cook (Member # 203) on September 27, 2005, 06:22 PM:

Ugo,

Thank you for the response. I thought that soldered might be the case considering the fact that people are sending the boards back and forth for repair.

John

Posted by Antoine Orsero (Member # 41) on September 28, 2005, 12:49 PM:

Good evening,
My problem with my GS1200 is the reverse gear but not rewinding! The reverse gear maet one moment before starting itself! But if I press laterally and slightly on the relay, it start yourself immediately! I looked at the weldings of the relay and they appear good to me! I do not manage to know the origin of this breakdown!

Posted by Jean-Marc Toussaint (Member # 270) on September 29, 2005, 03:39 AM:

Antoine, did you check the little cogs on the rewind motor? A cracked or clogged teeth could be the cause...

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