Seeburg AY160 Selection problem 6x4 exploded

My name is Bob. Please forgive me if this problem has been addressed before....I am new to the forum. I have a 1961 Seeburg AY160 which I rescued from a barn about 7 years ago. With my limited knowledge of electronics and with the help of Ron Rich’s Mech Guide and by studying the Seeburg installation and troubleshooting guides I managed to restore it to working condition. In fact it worked perfectly for the next 5 years. Then I noticed that gradually fewer and fewer of the records selected would actually get played until one day I started having the classic scan twice and stop problem. My next step was to partially re-cap the Tormat selector unit….I replaced all the paper and electrolytic ones. Then it did work good for a few weeks…..however, it became erratic again. So I used the trouble shooting guide and decided to replace the OA2 and 2050 tubes. Result was that the 6 X 4 tube exploded and the large power transformer smoked and burned. So next I bought a working Seeburg AY100 on Craigs List. I installed the Tormat Selector unit from the AY100 into the AY160 and WA-LA! it worked perfect for a couple weeks. Then the same old problem surfaced again….it would not play all the records as selected and reverted back to the scan twice and stop problem. So I changed the paper capacitor (C506) in the pulse amplifier with a good one….still same problem. Next I started changing tubes. After I replaced the OA2’s and the 6 x4…guess what….the 6 x 4 exploded and the transformer started smoking. I unplugged the jukebox and am hoping there is little damage to the power transformer. Next I replaced the 6x4 socket and replaced all the tubes with different ones. I Still have the scan twice and quit problem. I went through the trouble shooting sequence again and I am able to select records during scanning by temporally jumpering from A to B on the test strip which causes a record to be selected, played and returned to the magazine. Sorry about all the rambling on and on but I am hoping that someone has had a similar experience and can help me get this machine running again.

Hi Bob,
If I were working on this, I would slide the amp away from the TSU, remove the AC plug for the fluorescent lamps, then apply power to the TSU, only in series with a sixty watt incandescent lamp. This should protect the transformer, when you power it up and check voltages--something's "not right " ? Ron Rich

Hi Ron,

Thanks for the fast response. Actually I am able to cause records to play without additional smoke or damage at the transformer. What I did was I change the AO2's as I suspect that one may be possibly shorted....then I installed a momentary type switch with long enough leads so that as the mech is scanning I can push the button and cause a jumper between the A and B terminals at the test strip. By doing this a record is selected and plays. Otherwise it scans twice and stops.

Ron,

Unfortunate that I do not have a tube tester...so I can only guess about the condition of my tubes.

Bob, you are out of your element here.

Some points that need to be made here:

-Anytime a transformer smokes it is done. Smoke indicates that the insulation doping on some of the windings has burned off and that the insulating paper layers are burned as well. It is not safe to continue trying to use it this way.

-Any electronic unit of this age -must- be totally rebuilt with all capacitors replaced, fuses added and carefully powered-up while monitoring voltage levels. This is a one-time procedure but necessary when equipment, especially transformers, have been dormant and stored on unknown conditions for some time.

6X4 tubes are notorious transformer killers. I know I'll get some disagreement here but the close proximity of plate and cathode renders them susceptible to flashover and shorts. Seeburg's lack of fusing compounds the matter. At the very least a 500ma-fast fuse should be added to pin 7. I replace the 6X4 with two diodes in series (for added safety) and a approx 200 ohm 5 watt resistor in addition to the fuse.

What happened to your two selection receivers is likely the result of bad filter caps shorting and killing both tube and transformer. 0A2 tubes can not short unless one if actually broken.

If the transformers weren't ruined, I'd suggest it might be possible for you to order caps and DIY

At this point I suggest having -both- amp and selection receiver(s) rebuilt by someone familiar with this equipment.

Tinkering will just make things worse and possibly unsafe.

Rob/NYC

Rob

I appreciate your sound advice and for sharing your wisdom with me...you're right.... I am in way over my head trying to deal with this. I do know of a man here in Michigan that rebuilds Seeburg Amps and TSU's. I will share your advice with him and get these components properly restored by a professional.

Thanks again,

Bob
Brooklyn, MI