Having a weird issue with my Gorgar. When I start a game there will be lamps randomly lit, and turning on and off. The lamps that are lit don't correspond at all to what I know should be happening. Scoring and sounds seem fine though. This behavior seems to correlate with heat -- when i first fire up a game it seems normal, but after it's been on a while it starts acting bizarro.

The other strange thing is it operates perfectly in test mode. Attract mode looks perfect, and all lamps flash when they should in test mode.

I should note that the MPU had pretty substantial alkaline damage when I purchased it. I went through it pretty deeply, removed all corroded parts, cleaned up traces, neutralized, ect. all sockets were replaced, as was the 40pin. I do recall the legs on some of the chips being very black. I cleaned them off, but I wonder if they were damaged? I don't remember which chips it was unfortunately.

Solid advice. Will do and report back. A shorter wire or something would cause issues in game but not test mode?

okay, so i searched high and low for any pinched or shorted wires. I found some diodes that were sus looking and too close to some metal tabs but nothing other than that. Powered on and started a game. Everything working 100%, doing what it should.

Powered the game off and back on. This time I let it sit for around 20 minutes. Tried to start another game and it started acting all bizarre again. I touched literally nothing from when it was working fine.

no, but i just tried it again. All lamps flash in unison in test mode no problem.

one new thing i noticed is after ball 3 when the game dropped back into attract mode, the 2k bonus lamp appeared to be flashing in unison with game over rather than the attract mode pattern. Could be something to that.

Ugh. This is my fear.

Any guidance on how hot is too hot? The Lamp matrix PIA felt pretty hot to me, but i don't really know whats normal.

Does look toasty.

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One thing I didn’t do is update the TIP 42s and the 27ohm resistors. Mostly because the resisters looked like they were recently replaced. Wonder in that upgrade would help. Also wonder if the PIA is shot.

image (resized).jpg

Yes, the previous owner put those in. Those are 27ohm 5watt like pinwiki recommends. I think the preferred upgrade is to Remove the Tip42s and jumper the resisters.

https://pinside.com/pinball/forum/topic/vids-guide-to-bulletproofing-williams-system-6#post-594573

That pinwiki does say that heavy heat damage could mess up IC13 and 14. Those may need replaced.

Here are some videos demonstrating the game starting from cold, after it’s warmed up for a 5-10 minutes, and after it’s been on for 20 minutes or so. https://www.dropbox.com/sh/hmppm8j1f70t3pq/AAD-pm4WpiIoUKrlOgWPAIC6a?dl=0

Also note, i forgot to mention this is a retheme so it won't look like Gorgar. But it is indeed Gorgar

One thing I noticed while filming this -- it is not simply the lamps that are randomly lighting. The game seems to be honoring their state. For example, if one of the bonus X lanes decides to light itself, rolling over the other two will complete the set. Likewise if the magnet value increases to 30K on it's own, hitting the magnet switch will collect that value.

This has to be an MPU issue right? Maybe the game ROMs are corrupt?

Swapped in a different driver board. Seemed to last a little longer, but the problem still came back.

Also swapped out the ROM and CPU chips. No help.

I replaced both ram chips and problem persisted. Gonna take it out and double check my solder job on the new sockets but other than that I’m stumped.

Update and bump. I found a Spare GORGAR game ROM and popped it in. (just the game rom, not the two flipper ROMS). Problem persisted.

I got a loaner board from a friend. It didn't have any of the Flipper ROM or game ROM chips on it, so I transferred them from mine. Wouldn't boot immediately-- something wrong with CMOS RAM. Transferred my NVRAM over there and it booted up. Started a game, then after a few minutes, the weird problem started again.

So now I'm thinking it must either be the flipper ROMs or the NVRAM. Not sure if the NVRAM makes any sense though.

update again. Swapped the NVRAM with a 5101 and problem persisted. Gonna try out new Flipper ROMs tomorrow. Fingers crossed.

New Flipper ROMs did the trick.