I've been working on fixing up a Gottlieb Rock for a friend for the past month. The machine was in rough shape. When I got it, a bunch of fuses were blown, the outhole, 4 and 5 bank drop target solenoids were dead, and the knocker was stuck on, the game would lock up, etc.
I've worked through all those issues -- rebuilt a lot of the driver board and replaced Z30 on the control board.
Everything is working well now except for the 10,000 lamps - L47 and L51. During attract mode (and gameplay) these lights should alternate. I verified on a real game at Pinfest last week.
The behavior I'm seeing is strange. Sometimes when I turn on the game L47 will be on, other times L51 will be on. During attract mode, the light will look like it wants to alternate (ie, just a hint of dimming) but is on solid. Ocassionally during game play, (very rarely) the lamps will toggle.
Using the info at PinWiki, I tested Q48 and Q52, R48 and R52, and these are within the tolerances.
Using a logic probe, here is what I'm seeing on Z12 during the lamp test:
- Q1, -Q1 L44, L48 work as expected
- Q2, -Q2 L45, L49 work as expected
- Q3, -Q3 L46, L50 work as expected
- Q4, -Q4 L47, L51 do not toggle, L47 is high, while L51 is low
- D1, D2, D3, D4 work as expected. D4 does toggle (as I would expect) in the lamp test for Lamp 47.
I was all set to replace Z12 74175N, until I followed the test at: https://www.pinwiki.com/wiki/index.php?title=General#Testing_an_integrated_circuit
All the values are within the tolerances, and match Z11, etc.
Anyone ever see this issue before?