CED VideoDisc and Player Discussion

[lynx]

For a long time, I have been very slowly repairing my RCA model SFT 100 W CED player by doing my research on how to do it myself, and I have another question.



My player still has the common problem with the colours going in & out every few seconds, which is caused by the turntable spinning either too fast or too slow, instead of exactly 450 revolutions per minute. I watched the 2018 CED workshop video on You Tube for help again, and 21 minutes in to the video, while the technician was servicing a player similar to mine, an English attendee mentioned a two-speed gearbox as being a potential cause of the speed problem, but it wasn't clearly explained in the video how to adjust it. I must have failed to notice it the last time I watched it, and I now surmise that it could possibly be malfunctioning on my player.



Going thru the archives here on cedmagic.com, I can't find any reference to this gearbox anywhere or any old messages about it, although I found a paragraph about the turntable motor speed adjust in my RCA SFT 100 W service manual on the CED-1 Addendum-2 page with instructions on how to adjust it, and also similar instructions on page 37 of my equivalent Sams service manual.



Here are my questions: Does any one know anything about this gearbox, and would it be a good idea for me to adjust it? It's also my understanding that the turntable must spin at exactly 450 RPM for proper picture colour, so why would the player have two speeds? I'm a bit confused about it.



Thanks again for all the assistance; I really appreciate it!
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[jsdspif]

I've never heard of that. I thought all the f's and g's were belt drive. There is just a motor with a pulley on it,the belt is on that pulley and around the turntable and there is some sort of quartz thing or something that keeps the speed constant,i don't think there is a way to adjust that. The shaft of the tt may need to be lubed.If the belt is new it may need to be stretched because if it is too tight it won't spin fast enough. I put a new belt on a player and it wasn't spinning fast enough,put the old belt on and it spun fast enough. I let the belt stretch a couple weeks and it then worked fine. I used a handheld tach to check the speed. Used an old disc to stick the little piece of reflective tape for the tach to read the speed. The tach was like $10. could be the motor needs cleaned and lubed,belt slipping?
Are you sure "2 speed gearbox is what he said,i just thought there's belt drive or the j's and k's are direct drive. Also,do you have a spare,known good cartridge you could try?

[SelectaVision420]

the magnet in your turntable is likely weak. the belt is only to get the table up to speed once its at speed the sync plates drive the turntable, which is why their proximity to the magnet in the turntable is important for feedback. I believe that is how it works...
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