I am experiencing an intermittent problem on Gottlieb Altantis. Approx. once every 1-2 games, after scoring one of the 500 point rollovers switches (note: the numbered rollovers on the right or the rollovers up top - BUT NOT the rollovers that would advance the sequence, just the unlit ones), all scoring of any other 500 point non-sequence rollovers just stop. Also, oddly, the white drop down targets will not score either.

When this happens, it does not look like either of the C or D relays is stuck on. Activating any sequence rollover or blue drop target will seem to reset whatever the issue is and scoring resumes on all targets. Also, if I turn the motor wheel 1/3 revolution, this also seems to reset it.

Background info: Prior to this happening, I was working on a different issue, where the #1 sequence light was not activating upon game start. The problem was with the stepper unit, the contacts were not lining up correctly. I figured out how to align everything and solved that problem. I only mention it because of the timing and perhaps I made a mistake somehow and caused this?

Any thoughts where to start? I was going to start looking at the motor switches, but I don't really want to start messing with things without knowing what I'm doing!

Thanks for any help. I have a schematic and can try to digitize it to post if it will help.

When the scoring problem happens, the C relay does not activate, the motor does not turn, the machine is completely silent. If I use a bamboo stick to activate the C relay manually, points score and we're back in business until it happens again.

I took a picture of the schematic - is this telling me that Motor 1C is a switch which is normally closed but might be dirty or out of alignment which is causing the inaction? If that is true, I can see in the second picture which group of switches is the 1 Group, but is there a way to isolate which switch is the problem?

Or am I totally off base? Thank you very much for your help.

atlantis1 (resized).JPG

atlantis2 (resized).JPG

I am happy to report that there were a couple switches at 1C which were both dirty and making weak contact. After a few adjustments and cleaning, I was able to play 6 games without an incident... so I am cautiously optimistic this is resolved and even if it isn't, I have a good idea now how to handle it. It's nice to be able to enjoy Atlantis again!

I appreciate your help, thanks for your time and helping me learn a few things!