Demolition Derby
Demolition Derby January 14th, 2007OK…the insanity continues. 
We picked up another game in Hudson, MA called Demolition Derby. It’s from 1977, and is the oldest in our collection.
I was on the fence about this one, but Linda had to have it. She likes driving games. This game has a black and white monitor, and very old looking graphics. Everything on it is in great shape for it’s age. I really like the shape of the cabinet, and the backglass with the old cars smashing into each other. The game has one small problem. Where the score and time should be at the top of the screen just shows white blocks. I checked the voltage going to the game board, and it was low - 4.4 volts. I upped it to 5.1, and the blocks started to appear different. They are now all jittery and you can sometimes see the numbers. This leads me to believe that the problem is not with the game board, and may be with a big blue filter capacitor in the power supply. I’m going to try to locate one and see if it fixes the problem. You can see what it looks like now in this video:
January 16th, 2007 at 2:22 pm
Very nice find, that cabinet is in INCREDIBLE shape for it’s age. I’m so jealous of your game room
January 16th, 2007 at 2:44 pm
Thanks! I got it for $150, which seemed like a good deal to me. I’m hoping I can fix that score display problem. I’m ordering a filter capacitor from Bob Roberts today for it, and will post on the results when it comes in.
January 23rd, 2007 at 3:54 pm
I’m glad that it made the trip safely from Hudson and that you already appear to be making some ground on the display issue. It would figure that it may just be a cap problem when I was digging right into the board logic during troubleshooting. I’ll have to keep an eye on your site here for progress on it.
January 23rd, 2007 at 4:49 pm
Hey…thanks for posting.
I’m pretty clueless with this stuff, and posted in the forums at klov.com to see if anyone thought I was on the right track. Someone said probably not in their opinion, and it probably is something failing on the board. I bet they (and you) are probably right, but I’ll know soon when I change the capacitor. The replacement should be here Wednesday.
I got a bit excited when upping the voltage made the numbers appear a bit, but I guess maybe a bad component in the circuitry for the score and timing could start to operate a little better when more voltage is applied. I’m just guessing at all of this. I hope it’s the filter, because I can’t solder for crap. I have very little practice doing it. If I get lucky and find something I can fix on the board I’ll probably do a lot of practicing soldering on a board I don’t need first.
January 24th, 2007 at 8:38 am
I stumbled upon your link in a post on the KLOV forum. Otherwise, I may never have found the place
As an aside, you expressed some interest in Baby Pac-Man while you were up here. My wife seems to be willing to part with it. If you’re still interested, email me directly and we can talk about it.