Rock-Ola 447

Question. I have a Rock-Ola 447. When I push the buttons to make a selection the write-in carriage will start to spin and then stop after a second or two and then nothing happens. The record basket does not move. If I flip one of the levers on the write-in carriage manually, normal operation occurs i.e. the write-in carriage spins and the record basket spins, finds the record and plays it. I removed the write-in relay and stop relay and cleaned the contacts, switched their places even but no improvement. The play control relay is not attracting during normal operation. The play control relay does attract in scan mode and the record basket spins. In testing the play control relay coil there is 33 VDC on both sides of the coil when I test each with ground. Is it possible the coil is bad or other thoughts/suggestions? Thanks.

Look at the sequence of events in the Service manual. I would hazard a guess that the coil having 33 volts on both sides indicates it's good--
Ron Rich

OK I'll check out the sequence. Thanks.

Hi

If you are seeing 33V DC on both sides of the play relay coil, then that not only indicates that the coil is good, but also that the coil
is not being activated. For the relay to be activated you should see 33V on one side and next to nothing on the other, assuming of course that the coil
is ok. If you are unsure, pull the relay and measure the coils resistance.

Get yourself a service manual too, if you do not already have one.

I think the Play control relay is activated by the wobble plate switch, this is located on top on the selection pin bank, and also by the "Homing wiper contact" on the end of the main mech spindle (read out carriage end). This is actually in parallel with the wobble plate switch. When you manually flip a pin, this should close the wobble plate switch.

You mention that making a selection causes the write-in motor to run, and the carriage to rotate, this then stops a few seconds later.
When it stops, has it actually written a selection (toggled a pin) ? . If not check the hammer solenoids etc.

Pete

I've been checking the sequences and got narrowed down to Sequence 7 and 8 since the write in carriage would stop over the pin but the hammer wouldn't push it down. According to the wiring schematic the pink wire leading from the slo blo 1.6 amp to the stop relay should have -33 VDC and I'm getting about -40 VDC and the 1.6 amp slo blo selection system fuse is blowing. Also there is about -40 VDC on the purple power wire leading into the fuse. Thoughts on why the voltage is too high?

DD,
I think the 40 vdc is OK--I don't think it is a regulated voltage--but you might check the schematic, on that--
I would suspect a bad coil--I don't remember, how many WI coils are on that Mechanism--and have you (resistance) checked them all with a meter ?
The fuse blowing would indicate that either a coil is shorted (common problem), or that something is holding that circuit energized too long--
Ron Rich

I checked the resistance on all the coils on the write in and they seem good. I replaced the 1.6 selection system fuse and I can get one record to play before it blows. After the record is finished and put back in the basket, the 3rd digit number is stuck down and the lockbar solenoid is still energized. Looking at Sequence 9, the Attract Delay Relay (ADR) is supposed to disconnect power to the lockbar solenoid which de-energizes it and releases the 3rd digit number. When I watch the ADR during the one record play it does pull in and out like its supposed to (and the coil seems good when tested for resistance), but apparently the lockbar solenoid isn't getting the message to release the 3rd digit thereby holding the circuit open and blowing the fuse.

I had to special order 1.6 amp slow blow fuses online since I couldn't find them locally. Is it ok to use 1.5 amp slow blow fuses since I can get them at Radio Shack? I figure a tenth of an amp on the safe side? I'm going through several fuses while I try to track down this problem in my previous post.

It is always "better" in this type situation to use lower value fuses--but you also must consider that a lower value fuse may "blow" without any problems existing-
Ron Rich