Technics SL-1210MK2 - weird speed problem

same break trimpot at maximum problem on start TT

Well... I found the culprit. I atually didn't know that having the Brake pot to the maximum clockwise position was actually making the platter goes backwards... Had to go to the maximum counterclockwise position to calibrate it properly. It now doesn't spin back anymore and doesn't move either when I turn the deck on !


-> i was have a Pair of SL-1200 MK2 and only one sl-1200 mk2 with this same issue on start/stop (ON START)

sometimes when im was push start turntable the platter spin back 5cm and go forward ok without problem... it was not aways...
and i discover something: when im decrease a break on TRIMPOT to less force the problem was never happend again ..

maybe some capacitor or resistor with problem on start/stop line ... one mk2 dont happend and other happend with break near to maximum

you replace An6675 and An6680 and this problem not gone .. i assume that the 2 Chips is not responsable for this issue

maybe C214 (10v with 100uf) or D204A or R215 (that feed the trimpot with voltage)

all the best for all
Imageshack has decided that what was once free should now be paid for, so the scope screenshots in post #74 are gone.
Updating by re-posting image here, original post can't be edited.

Here's the comparison.


Another thought is that maybe the output driver on pin3 in the AN6680 goes faulty then changing R307 comes as a solution but IC201 could be the real cause, I have none at hand to check.