Rock-ola 448

Look at the schematic--the wobble plate switch and the RO slip ring, are probably wired in parallel-should read open if mechanism s "homed"-if I remember right---
Ron Rich

I was out of town for the weekend but getting back into it now.

Ron, you are correct. In looking at the schematic it looks liek the brown cable from the wobble switch can also make connection to ground via the homing wiper. I did not think of checking this before. I looked at the wipers, and they are stuck in position NOT on the break. I checked for continuity and it broke when I lifted the homing wiper. The carriage is STUCK in that position, so I can't rotate it to the break in the circle. Since the system is supposed to start with the homing wiper in the break, I don't know if this is causing a major disruption in the sequences. I would like to rotate it, but I don't know what is holding it there and don't want to break anything.

I don't know if the play control relay is being charged or not, or whether the problem lies with the #1 micro switch. I will be measuring the voltage on the switch this evening and see if it is getting any juice.

Thanks,

My debugging skills may not be up to par at this point.

I installed the wobble plat switch again, and was trying to determine if the #1 micro switch is working when I decided to test the play control relay. I pushed the relay into action with my hand and table, carousel and carriage arm all rotated as they are supposed to! I greased a couple of areas to reduce the screeching sounds. Lights in the lite box all work and blink (except for #1 which I can deal with later.

I looked closely at the relay and the rectifier has some slight discoloration on one side, dark brown stain-like. I think maybe it is bad, but the multimeter test said it was good, so I am not sure. What do you think the best way to test the relay would be?

Thanks, much appreciate it as usual.

-Carlos

Carlos,
I am ASSUMING, and going by my great, but not too long memory here----
If this is one of the "interlock" relays, you should be able to remove power, un-plug the "box" and measure the relay terminals--any resistance should indicate a "good" coil--you might check the reading against the "sister" relay coil---but be very careful, not to put any pressure on the solder tabs, as all "Guardian" brand relay coils suffer from a fatal flaw. They produced these with too tight a winding, and if the tab is pressured, the wire tends to snap, sometimes at the lug, other times in the center of the relay coil. Ron Rich

Hey, Guys.

I replaced the diode attached to the relay, thinking it was bad, but it made no difference. I don't know where to go from here. The operation switch is good, i tested the connections. Any ideas why the relay may not be working or a way for me to test it??

Thanks!
-C

Carlos,
Did you see my post above ?
Remove one diode leg for testing--
Ron Rich

Hi

This is all getting a little confusing, maybe I can help clarify a few things.

As Ron said earlier the purpose of the wobble plate solenoid is only to help the first pin be selected.
Once any pin is selected the wobble plate switch will close, and stay closed until the very last record has been played (all pins reset)

This switch and the homing wiper are wired in parallel and supply power to the play relay coil via the operate switch (must be in operate position).
The play relay will then be actuated continuously, turning on the turntable motor and supplying power to the motor control box, interlock relay etc, until both
the following conditions are met.

1) The last pin has been reset (wobble plate switch opens) Confirm the operation of this switch only with the carriage in home or by pulling a wire from it, cos its
in parallel with the homing wiper remember.

and

2) Carriage assembly has returned to the home position, (both switch and wiper open).

When these conditions are met, the relay will then drop out and functions will stop.

To test the play relay, I would remove it, then check first for power at its coil connections in the socket.
There may be a resistor in series with the relay's coil in the PSU box, and almost certainly a diode across its coil to reduce back EMF.

If power is getting to the relay connections, and the relay itself does not operate when plugged back in then most likely it is faulty.
You may even find you can remove the plastic cover from the relay and check for coil power with the relay plugged in.

Finally as confirmation check the coil's resistance with your meter on its Ohms range (out of circuit of course )

Pete