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Magnavox Micromatic auto-start issues

T

ThreePints

New Member
Hey Everyone. I bought a 1965 Magnavox Astro-Sonic console with a Micromatic turntable that didn't turn. I rebuilt it by following the directions posted here by larryderouin -- and now it works! (Thanks, Larry!) The old grease had turned to gum and things were all seized up. Now, everything is cleaned and re-greased, so the idler wheel reaches the platter and turns it once again. But one issue remains:

The auto-start function still struggles. Sometimes, the wheel reaches the motor and it drives the cam wheel. Other times, it doesn't. When it does, the record drops and the tonearm lifts, moves about halfway across the record, stops, returns home, drops, and the record shuts off.

Now that the platter spins, we just play it in the On setting and position the tonearm manually. It plays a full LP without issue. But, it would be nice if the auto setting could do its thing.

Is there a particular starting point for the cam wheel that is perhaps not in the right position when starting it up? Or another issue? I'd be glad for any advice.

Micromatic teardown & rebuild

I did a teardown and rebuild on another of my Micromatics I got Tuesday with the console. In the thread on Vintage Forum titled Another Maggie reprievehttp://www.audiokarma.org/forums/showthread.php?t=213517, the question of how to teardown and rebuild the turntable came up. This is the result...
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It's a Collaro changer and they work by the arm moving in until it hits the edge of the record to be played. This sets up little "gates" on the large cam to guide the arm which path on the cam to follow so it sets down at the right starting point. It's been years since I last repaired one of these so I may have a detail wrong but that's the general way they work.

You just have to look closely to see what's happening during the cycle to see what's going wrong.

Doug
 
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