Seeburg K/L pre-amps

My wife was playing the K and the Mech hung up on the left hand side. No problem. Power down filp the reverse switch and power up. Away the mech went. At the middle of the record carriage it stopped loaded a record and froze as if it had no power. Fuses all check good. Record will not reject and turntable will not rotate? Any ideas where the problem may be?

Thanks
Darrell

Darrel, check the contacts on the scan assembly (in sel receiver)

They often become pitted and erratic. I have several here that had melted the actuator that opens them. On the units I have in service I've added a 120vac relay that actually controls the mech and the scan just powers that coil.

Is the 5U4 lit? That section of the amp is parallel w/motor circuit.

Another test is to see if the manual reject will pull the trip lever. If yes then that pretty much confirms a motor/AC problem.

Rob/NYC

Rob, and all,
The scan control points/"plastic", burn for one or two reasons--1. the .1/14kv cap falls off them, 2. mis-adjustment, after the cap has fallen off-Ron Rich

Rob

Going through manual for third time trying to locate the contacts on the scan assembly (in sel receiver)? Cannot find parts labeled "scan assembly" or sel (ection) receiver?

The 5U4 is lit.

The manual reject makes no noise when pushed and will not pull the trip lever. I can manually move the trip lever, but nothing happens.

I can manually rotate the turntable by rotating the motor coupling manually.

Thanks
Darrell

Update, rotated turntable until it rejected record. Then hit reversing lever and the mech took off and is now playing playing records as though nothing is wrong?

Best
Darrell

Darrell, the scan assembly, or play control etc, is located in the pan of the chassis and has two coils that act on a white plastic piece that open the AC to both amp B+ and motor.

However, from what you now describe it sounds like a section of the motor-run capacitor (that large can on the mech) has a bad section. There are two sections to that cap; one is always connected and the other added only in scan/changing and removed during play.

If the play section has lost capacitance there will still be barely enough capacitance to run the motor when both are connected, but not quite when the extra section is removed as the mech approaches the play mode. This would account for the occasional stall during scan.

The fact that the trip button didn't work when pressed probably just means that the mech stalled at a point just short of where it gets connected.

If you have a non-polarized capacitor of approx 1mfd @200volts or more (mylar is good) try tacking it on to one section of the motor cap terminals. Connect between the "common" on top of the cap and either of the two sections. I don't have a schematic handy to tell which of the three connections is common, but the always connected one goes to the green motor wire and the scan-added one goes to the contacts on the vertical stack.

Rob

Rob
Thank you for the information, it is very useful.

Best
Darrell