Any one seen this phenomenon before and know the fix???
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Beogram 7000 turntable starts spinning of it's own accord. Look, no hands!!!
16 replies
Not yet, only the platter is spinning or does it start playing? (Record on of course)
Not yet, only the platter is spinning or does it start playing? (Record on of course)
Just the platter spins, it doesn't start to play. It sometimes does it with no record on!
Check for free movement of the dual-headed start/stop solenoid.
Check all the mechanically operated microswitches, their tiny square springs can sometimes come off, leaving the affected
switch constant on or off.
Martin
1S1 causes the platter to spin. It's located on the bottom of the triangular shaped pcb near the big gearwheel. It's also possible that the diode D9 became defective.
Check for free movement of the dual-headed start/stop solenoid.
Check all the mechanically operated microswitches, their tiny square springs can sometimes come off, leaving the affected
switch constant on or off.Martin
Solenoid is free to move, I've never seen a tight one! Micro switches all check OK.
The motor is not getting full voltage as it is almost but not quite at a standstill. Maybe spinning at 10 rpm and no torque. I can stop it with my finger and start it again by turning the platter. Weird
Double post
1S1 causes the platter to spin. It's located on the bottom of the triangular shaped pcb near the big gearwheel. It's also possible that the diode D9 became defective.
Defective diode is a possibility. I'll change the board for another and see if that cures it and investigate D9 later.
The motor is not getting full voltage as it is almost but not quite at a standstill. Maybe spinning at 10 rpm and no torque. I can stop it with my finger and start it again by turning the platter. Weird
Ah! That could be the transistor TR6. It switches the supply voltage for the motor. Maybe it's leaking.
Sorry for my earlier post. Diode D9 cannot be the fault, it is conducting, when the pickup has moved in (1S1 closed). I wondered about the circuit in the manual, which i downloaded. It is a little blurred around the motor. So in the printed version it's clear.
A replacement board would cure it, no doubt, but else TR4 / TR5 (both BC337 - you have those) and
also TR6 and TR10 could be at fault.
You already replaced one leaky BC337 - it was in this deck too, right?
Could be a bad batch.
Martin
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