Sunday, June 19, 2011

Arm will not lift automatically on Thorens Turntable

The auto lift stopped working. What had happened was that the trigger get raised on the tonearm out of the zone the sensor could read.

You'll need to flip over the TT and remove the bottom cover. Remove the cover protecting the tonearm wires. MAKE A HISTORY MARK NOW! First check that the sensor is not too far away from the trigger. I think the manual says .5mm to 1mm gap (.020" to .040"). Loosen the screw and rotate the trigger cylinder one way or the other and see if the function works. A little bit of change at the pivot makes a big difference at the end of the arm.

If re-timing solved your problem, re-tighten the screw, button her back up and you're done

If it did not solve your problem, you can try adjusting the height of the tonearm. If that fixes your problem you them have to decide if you can live with the tonearm position. If yes, you're done. If no, read as follows:-----------

The fix is to fabricate a small piece of ferrite (mild steel would probably work) and adhear it to the trigger cylinder.

Everything should work fine again now.








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The white cylinder has a metal plate molded into it. That metal plate activates the orange sensor when it comes into the correct relationship. I believe the metal plate has to span the upper and lower portion of the sensor. That will be apparent when you remove the sensor and examine it. using ferrite. That material has properties that come close to what the sensor was designed to work with.



The amount raise arm requires you to modify two other pieces. The tonearm lift needed to be taller so remove their rubber cushion (just slides out) and glued on a piece of automotive vacuum hose.



The tonearm dock also needed to be raised so you can fabricate a 1/4" spacer out of lexan and paint it.



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lower the arm back to the height where the auto lift will work THEN modify the lift arm so the tonearm achieves the proper relationship with the vinyl.

If all you needed is a little more height for your tonearm lift, by all means lower your tonearm and add something to the lift arm.--------