NOOB ALERT! -- I know electrical to a fair degree, but am almost fresh to EM work on pinball.

Machine: KING KOOL Gottlieb '72

Status: bonus ring of green lights doesn't work; all lights flicker a bit when spinners spin (brighter towards lights 7-8-9), no sense of progression until it flips out and tallies 5x1000 bonus lights in a row and settles down again to doing apparently nothing....

Check the photos. That's (as far as I know) the little stepper motor going to the green lights. Connections for C, 0-9. Connected by jones plug. Everything looks OK, the plastic cogs and cams look good and function manually to trigger or release the two switches. Dial on copper connection side spins fine, looks good and clean. Lights were replaced, wires seem fine. Previous owner cleaned most switched I find, but I don't think he cleaned these.

I need to clean the switches, but have no rubbing alcohol in the house. What might work? I do have some EVERCLEAR.

Has anyone had work on this G-unit motor in KING KOOL/ROCK?

Any idea why the 1000 BONUS lights might rocket forward with each 10 point score rather randomly? Could it be related to this unit?

Thanks for any help.
IMG_1245 (resized).jpgIMG_1246 (resized).jpgIMG_1248 (resized).jpg

I was reading up on these units, and they are finicky.

I got mine semi-working today by using the Everclear to clean the copper-spider disk on the board. The turning mech works pretty well, that I can tell, however the problem is more about the lights being lit together at times or not being lit at all.

The arm connecting the contacts to the disk, the rotating arm, is a little loose. However, when contacting, it lights up one strong light and the rest are dimly lit. Is this a problem that can be cleaned or does it have to do with decay of the board?

Thank you for the reply, and the link.

I just used naphtha to clean the copper spinner board and will try it out again, however, I was having a slightly different problem with lights being on. The first light was STRONG and the second not so much, the third almost invisible, then 4-7 dead, then 8-9-10 all lit brightly together! I definitely understand the problem of two on together, but three? And the three stay lit through the sequence of 8-9-10.

Also, I might have a problem with the cam shaft not allowing advance at the point of awarding a 1000 pt bonus, because periodically it just pauses and award 4 or 5 1000pt advances in a row for each 10 points scored....then it continues normally again. UGH. I sense a rebuild in my future.

A certain amount of "gunk" has built up on the cam wheels which might be slowing down that advance point. The teeth of the shaft appear OK to me, bring good, coil works fine, all bracket pieces are solid, etc. I think the switches are also properly contacting to the cams and everything else is adjusted.

UPDATE: stripped it down, cleaned it, replaced the cam shaft and circuit board (spider board), adjusted the 10x stepper switch (nearest board), applied some armor all to the cam on the 10x stepper because the switch/cam were sticking when the spring got into the cam's "rut" and wanted to ensure a little extra slide.

RESULTS: WORKS.... kind of.

PROBLEMS: that new board by Steve Young doesn't have those metal-rivet ears on the holes, so getting the wires soldered perfectly to the metal has been finicky--lights are still hit and miss. Seems the 10 point hits give me TWO advances of the AS RELAY instead of one... is that CONSERVATIVE-LIBERAL setting?

EVERYTHING scores appropriately otherwise, and it works well enough to play properly. No more sticking, lights do work and don't light up 2 or 3 together. It resets properly as well.