Stars
Stern Electronics, 1978Everything is working normal, but noticed my tilt bob has stopped working.
All the wires are secure at the tilt bob and tilt roller. Diode located by the tilt roller shows open one way and 555 the other way on my meter using diode check.
The wires ring out OK from the bob/roller to CPU J3 pin 15 and pin 2 like the drawing shows.
I have no experience with the Alltek board. What next?
tilt bob (resized).jpg
tilt bob wiring (resized).jpg
alltek (resized).jpg
Did some more checking, had J3 off/on a bunch of times. Confirmed pins 2 and 15 measured open to ground. Put a jumper clip across the tilt bob and measured across 15 and 2, and as expected I could see the 555 from the diode and open with the jumper removed.
Played one more game, and now the tilt is working again!?! 
Quoted from Neal_W:Did some more checking, had J3 off/on a bunch of times. Confirmed pins 2 and 15 measured open to ground. Put a jumper clip across the tilt bob and measured across 15 and 2, and as expected I could see the 555 from the diode and open with the jumper removed.
Played one more game, and now the tilt is working again!?!
Maybe a flaky J3 connector? or the game just wanted to throw you for a loop
Quoted from Knxwledge:Maybe a flaky J3 connector?
Not expecting a low power connector to act up, buy maybe. At least it seems it's not a bad board, since it is working again.
Quoted from phishrace:Tilt bob looks grungy. Lightly sand that and the ring.
Agree shiny is best, but this thing was 100% dead, even grinding the bob against the ring did nothing.
Check and/or replace terminals in the connector. Regardless whether it’s a low voltage connection those old pins fatigue/oxidize and eventually fail causing janky connectivity issues. I’ve found a bunch of terminals working on old ss games that looked good in the connector visually but had significant wear or fell apart on disassembly.
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Ramona, CA