Rock-Ola 447

I have recently come across a Rock-Ola 447 that isn't working and I am trying to get it going. It lights up and the turntable bit is rotating but I can't get anything else to move. The record arm is down and I can't move it. I can move the record cage by turning the knob underneath the motor. I can select the 1st, 2nd and the 3rd select numbers but nothing happens. I am thinking I'm not getting power to the motor? When I select the scan option it sounds like a relay is clicking in the main power panel? I have checked all of the fuses and they appear to be okay. Can anyone help me out with where to check voltages and what they should be etc?

Thanks,
SteveR

A few places to look:

- The pickup arm has no safety drive, which it would have on a consumer record changer. It should be immobile except when actually playing a record. Do not attempt to force the arm, or you will damage it.

- The credit unit may be preventing the selector from selecting a record.

- Check the power supply oputput voltages and fuses first.

- Check the motor or logic on the change sequencer. This operates the various parts in sequence for getting, playing, and putting back a record. The sequencer might be stuck in the middle of a cycle.

- Many parts have limit switches, which sense the completion of one portion of the change sequence, telling the sequencer to advance to the next stage. If one of the limit switches isn't working, the sequence will stop at the point where that operation finishes, waiting for the missing impulse. This prevents the parts from working, and also prevents manual operation of the record basket.

I got the troubleshooting manual for this machine and I have been going over it. The 10W 15A resistor in the control box looked fried and the wires around it had melted. I replaced it and fixed up the wiring and managed to get a few things moving but the resistor is getting incredibly hot! What would cause it to fry/overheat? All the selections are working fine. The scan doesn't work unless I connect the 30V to the orange/white wire on the microswitch. All of the motors work but not on their own. If I manually wind the motor to get the gripper arm up and then hit the operate switch the arm goes over the turntable and then cuts out all the while the resistor is heating up bad. Any suggestions??? The book suggests the resistor but I have replaced it.

Thanks,
SteveR

A 10-watt resistor will get hot. Otherwise, they wouldn't put in a 10 watt resistor.

Is that a 15 amp resistor (?) or a 15 ohm resistor?

Measure the voltage across the resistor.

If it is a 15 ohm resistor, then it will not overheat as long as the voltage is less than 10 volts. 12 volts is just below the destruction point.

Years of this heat can make the insulation in nearby wires change.

It is a 15 Ohm resistor and I will check the voltage. The machine was stopping just as the record was put on the turntable and the troubleshooting guide said that this resistor was the trouble. I replaced it and then it put the needle across onto the record. When the record was finished it replaced the record into the magazine and stopped. It felt like the gripper was jammed at the very top as it was hard to turn the knob on the bottom of the gripper motor and the resistor got very hot and ever since then I haven't been able to get it to play the record, the gripper motor stops when the record is on the turntable as it did before. I have replaced the resistor again and it still won't go any further. In fact the only way I can get it to do anything is to manually wind the gripper motor so that the arm is towards the magazine then switch it to operate and then verything moves as it should but stops once the record is placed. Has anyone had this before on a rockola?

The voltage on the resistor was 16 which is above the 12 which is the suggested destruction point. What would be causing the voltage to be so high?

SteveR

This sounds like locked rotor current in the gripper motor.

There should be a limit switch somewhere which tells the "brain" that the gripper has replaced the record. This switch should either make or breaqk a circuit to cause the cycle to advance to the point where the gripper lets go and the carousel revolves..

This switch is either not being actuated, or the circuitry it works is malfunctioning. Most likely the screws holding the switch in place are loose, or a wire broke off the switch.