rockola 477

Just acquired a rockla 477 from a friend, typical situation, lots to be
done. I supose for starters the power supply and amplifier are fine,
initially the magazine would not stop, cleaned the opto board it stops now
but not at the usual home position.I have tried the adjustments as outlined in
the manual but it does not seem to make any difference. The gripper arm is
now slightly above selection 110 when the machine is idle. In addition when
a selection is made the movement of the gripper assembly is slow- the
grabbing of the record is slow, so slow you could fall asleep, but the
turning of the record and placement on the turntable seems quick enough but
then the movement of the stylus arm to the record is slowwww and at the end
of the song the stylus arm is slow to return back to its position. The
gripper arm is even slower and at times breaks the 32vac circuit, eventually
the gripper arm tries to get the record but for some reason the end of the
arm lifts slightly and the record will not be lifted. Anyway the gripper
turns fairly quickly but then is very slow to get back to the home position,
so slow.
Would it be the lubrication on the gripper assembly or maybe a dying motor
Also how can the magazine be adjusted so that it should stop where it
supposed that is the home position when the jukebox is turned on
thanks
Sean

Hi Sean,
I´m pretty sure that it´s the lubrication. I´ve had a very similar problem with my 477 when suddenly the motor stopped working from one moment to the next. As it was not for an electrical cause, I opened the screw on top of the motor, put in some drops of machine oil (as used for sewing machines or bicycles). The motor started instantly working again and does so since. I suggest you do this with all your motors (turntable, tonearm, mechanism). The problem is that the grease became a kind of resin in the last forty years and blocks the gearwheels inside the motor. The oil creeps in everywhere and makes the wheels move again. If that doesn´t work your only choice is to dismantle the motors, clean all the parts and give them fresh grease. These motors normally do have eternal life and don´t die easily.

As you did the adjustments on the mechanism outlined in the service manual (page 61) and it didn´t help it may well be that the mechanism motor is blocked by a piece of "resin" shortly before reaching the proper position. Another cause can be the opto board. I suggest you unplugged it for cleaning. As you found out, you need a little bit of force to unplug and plug again. The soldering of the pins connecting the socket with the board is sometimes insufficiant and breaks in case of overtaxing (it´s also forty years old) . The socket shall fit tightly and should not be moveable . If it´s not fixed properly you´ll have contact problems when the basket is moving and problems in the positioning of the basket. A good indicator for the proper soldering is the little red lamp on the board. It should be off when the basket is at rest. It should be flickering when the basket moves and it should never burn continuously. If the light starts burning when you try to move the plug, the socket is to be resoldered.
Hope I could help you a little bit
Mario

Hi Mario
Thanks for the information and tips, it turned out that all of these items and the gripper arm assembly needed lubrication, once that was done the gripper arm moved fine. You sure have to dismantle alot of things inside the jukebox to carry this out but its a good learning process and it won't not seem as daunting again The problem with the home position was also solved, what had happened was that the plastic wheel fitted on the outside of the encoder wheel had slipped from its slot slightly( two slots) but was enough to move the home position. Now everything is working fine, the opto board gives occasional problems but can be rectified pretty quickly, the opto board even if pressed slightly will affect is operation
thanks
Sean