I take a bit of a break from working on pinball machines in this video and do some work on a Tempest video game I pieced together from various parts. The monitor started smoking and fizzing on me and then went completely out — which signaled a good time to completely rebuild it.
For additional information on working on these monitors, here is a good resource:
I get my parts from http://www.therealbobroberts.net/
I was having an issue with a Bally “Supersonic” pinball machine randomly resetting/rebooting. The problem was traced to irregular power coming off the driver board. In this video series I go over a necessary process to bring these old boards back “up to spec” as well as a few improvements that make the game overall more reliable.
In taking an initial look at the latest game I picked up, this Bally “Mystic”, as always my main concern is checking to make sure there’s no significant battery damage on the game. What’s interesting is when I looked at the game, there was no battery on the MPU board. The owners insisted the game saved the high scores, but I didn’t see how? Was there a battery on the underside of the board? I had to pull the MPU out to see.
What I saw was a board that someone had repaired, that had leaking batteries on it. They simply pulled the board and replaced a few damaged components and did not put a battery back in. But they created another issue by not fully-cleaning the board, and as a result, the damage from the leaking battery, even though it was long gone, continued…
The other day I was reminded of how important it is to make sure you fully mitigate battery acid leakage on circuit boards. A friend picked up a STTNG (Star Trek the Next Generation) pinball machine. I’ve been systematically going over the game trying to get it working. When I first looked at the backbox I noticed wires had been run for a remote battery pack – I thought “good deal, one less thing I have to worry about.. the MPU board is clean…” so I went about working on other areas of the game, checking switches and optos and everything. After I got the game booting up I discovered the start button would not work. After spending a bunch of time testing all the wires and connectors and still not finding the culprit I took a closer look at the MPU board where the cabinet switches plug in…
I have seen acid damage before, but nothing as sneaky and widely-spread as this. Components all across the main processing board were showing signs of corrosion and damage, but I could also see that repairs had been done, several components and ICs had been replaced and sockets added. Someone cleaned up battery damage and added an external battery pack. But there was still major corrosion on the board… what gives??
My theory is that whoever cleaned the circuit board, instead of using vinegar and multiple paper towels or q-tips, they probably used a single wipe, and in the process of cleaning the circuit board, actually spread the acid all over the components! At the time, they thought it was clean, but they actually made the problem worse.
This is why it’s very important to thoroughly clean off any leaked electrolyte from batteries, and use vinegar to neutralize it, and use multiple wipes — do not wipe from one area to another area. Work on small parts of the board at a time, throw the q-tip or paper towel away and use a clean one when you start to work on another area of the board. Do not risk spreading the acid to previously un-damaged components.
Another deal came my way recently and as usual, when you’re out of room and almost out of money, and someone offers to sell you a game, I threw out a pretty low number and it was accepted. Actually, I’ve been wanting to get a Black Rose pinball machine for awhile. These early Bally/WMS DMD games are quite good IMO, and they bridge the gap well between the older games and the more modern ones with extremely complex rulesets. Like its predecessor, Party Zone, Black Rose is a very fun game that doesn’t require curling up with a big printout to understand the ruleset and enjoy the gameplay.
However, first things first… when the owner told me they had no key to the backbox I suspected the worst…
And as expected, we had battery issues, but this looks like it was rescued in time…
Remember, the first rule is to neutralize the acid on the board and then clean it thoroughly. Then make sure everything is thoroughly dry before you put the board back in the game.