Seeburg L100 Random Selections, Some work, Some don't

Hi,
I have an L100 that I put all new capacitors in the circuit boards. I checked the tubes with a tester. I cleaned all the sliders on the selection buttons. Soldered all the holes in the RCSU stepper (128). I checked for continuity from the buttons to the side connector of the stepper. I also checked for continuity from the side connector of the stepper through to the top connector. All seems good. All buttons seem to be making contact to each prong. The 36-pin connectors are clean and tight. I have a manual and went through the Tormat Selection System Troubleshooting Procedure and everything worked well up to the H Test #1B and my lamp flashed - so it says I have a defective starting switch or an open circuit pin #31. Thirty selections play great. It sounds good. All tubes light up. Seventy selections don't play. It scans twice. My tormat pins are clean and flat and the rivets are clean. I have not replaced any resistors on this unit. Could bad resistors cause some selections to play and some not to play? I wrote down all the number/letters that work and don't work but will wait to see if you request or need these to be able to answer. Any help would be appreciated. This selection button and tormat system is so confusing.

You need to divide the system (in your head too)--between the write in and read out sides. Do you know how to use a D cell to set all selections to the selected state ? If so, do so, and see what happens. If not, it shows you how somewhere in your trouble shooting guide. There are no "different" resistors/caps used for any selections-- Ron Rich

Thanks Ron, I did do the battery test three times and the selector stopped at every number down the line from right to left. I am suspecting the problem may be with the write-in circuit. I don't know where pin 31 is (can't find it). Is it on the 36-pin connector? What I don't understand about the selector buttons is: Each number button seems to go to two different tabs on the 36-pin side connector.
Example: #1 selector button traces to A11 and B9 on the connector. #2 selector button traces to A12 and B10, and so on. The letters A, C, E, G, and J seem linked together and B, D, F, H, and K seem linked. Is there a way to test the selector buttons through the stepper, one at a time, perhaps using a test light or continuity test? Can the stepper unit be eliminated in any way?

Hi Joe,
You have proven that the problem is a write-in one--
Unfortunately, the K/L series phono's are different then all the rest in that they used that PC board plug, but the schematics, I have indicate the "normal", Cinch-Jones style. I would proceed by checking continuity on the failing items from the keyboard (with the button held down)
through to the Tormat plug. The stepper should not affect this reading, as the stepper, when pulsed only "adds" to it--. There is no practical way to eliminate the stepper, on this model, except if you can find one of the VERY rare, stepper elimination (TJU-1),("blank") boards.
If your problem is intermittent operation of ALL selections, I would suspect the "k" contact insulator in the pricing unit is "dirty", or the "finger" is not making good contact. You also MAY have a resistor, or two, that has changed value in the write-in circuit ? Ron Rich

Thanks for the help Ron. I will continue checking continuity and if that checks out, I will look at some of the resistors.

Hi, After checking continuity everywhere I could, I found no shorts, no broken wires, and seemed like good connections. I recleaned all side connectors and the tormat block and rivets. I tried it out and it would still miss some selections. BUT, when I tried pushing the number button first, then the letter, the selection played. ??? I tried pushing them, number first, for all the buttons - and they all played well!

I don't know why it works that way, seems backwards. But, it's playing and sounds good.

I haven't mentioned yet, but when I first got the machine I installed a "free credit" unit from Vern Tinsdale. The original credit unit was burned up.

I am glad it is working now. Thanks!

Hi Joe,
The usual cause of that symptom, is that the latch bar is not correctly adjusted--Check the SM, and see if you can tighten it, just a hair, so the letter buttons are held down further. Ron Rich

Hi Ron, I will look into that, and adjust the latches as per the manual. Thank you. Joe