Picked up a 1987 Gottlieb Monte Carlo. When bought, it wasn't starting a game, but it was at least showing some messages (switch closed, tilt, etc). Got her home and re-seated board connections (hoping that was a quick fix), checked and replaced where needed all fuses -and powered her up -now nuttin. A repetitive clicking sound comes thru the speakers, LED light on the sound board stays lit, the ramp coil fires and stays on, "sometimes" the display will show one or two rows of symbols - in sync with the clicking.
When I unplugged one of the ground molex connectors (A12-J5) - playfield lights come on, the flippers & kickers work when hit and the roulette wheel stays on constant. The ramp coil releases. Plug that back in and all reverses. So although I've read about the ground mod on Pinwiki for these, I took both groupings apart and all look clean and making contact, and this looks like they are working (Could do the mod, but don't think this is the main issue). The boards do NOT have the individual grounds as I've seen in other posts. I have NOT checked the large capacitor on the ground/transformer baord. (I need the manual / schematics and will get those ordered today from Steve)
There is no "Re-set" board, someone had already removed it. From reading past posts, for home use, this is not mandatory - correct?
I did lightly press on the daughter board - to check for possible solder joint issues, but no changes and "seems tight" but can't visually check, but again, no changes as pressed. PROM's bad??
On the Display board, I do notice someone had replaced "C4", but "C2" looks funky??? Again from reading Pinwiki and past posts on these systems, the display board handles a little more, so possibly this is keeping her from booting up?
From the CPU connector - A1-J2, the cable splits and goes to the display board and another 9 pin connector (see photo). This connector is not labeled, but next to the one labeled A9-P1 / A9-J1). "Sometimes" (why it's sporadic?) when I unplug that connector - I get the attract music and GI's lighting.
"Sometimes" the topper lights all work as well..it's all very sporadic overall....
Going to have friend and mentor go over the boards, but thought I'd ask here for any tips or irregularities anyone sees that I may be able to fix on my own - or things to even check for. I see the small "stars" on the boards - are these TP's or ground spots? Which location and what readings should I be seeing at the various locations? Such as the large cap on the ground/transformer board, or the 5v small board with the heat sink? I see the pot to adjust, but where do I check actual voltage?
Sorry for all the questions, but thought I'd lay all the issues out there as I see them...Hope the photos help some.