modessitt
Volunteer: Encyclopedia Submission Moderator
So a few weeks ago I had a Defender CT in the shop to rebuild the monitor. While I had it in, I looked over the rest of it.
The customer bought it from a shop a year or so ago (who didn't recap the monitor before selling it). The RAM had been upgraded to 4125's (with a trace cut) and the CPU had been modified to composite sync (with a trace cut). It also had a switcher installed, even though the original PS is still in there and has all the power LED's lit. It seems they left it to power the coin door and control panel lights. I also noticed that several of the ROMs had legs that broken off, and had clipped leads solder to them as replacement legs. Since the game seemed to be running fine, I didn't risk removing them to clean the legs, but maybe I should have.
Anyway, I noticed that touching the ribbon cable between the ROM and CPU boards caused the game to reset, so I replaced both ribbon cables with new ones. No more resetting when flexing the cables. I also reflowed all the connectors, fixed a bad wire to the volume pot, redid the monitor, installed new AA batteries, etc and everything was working fine.
Well, the customer called and told me that sometimes - after the game has been on for a while - it will either freeze while he is playing, or sometimes go to the rug screen and stay there. He tells me that when he first turns it on, it comes on just fine and plays fine. But if he leaves it on, later he'll come by and see the rug screen up. Or he'll start playing and it will freeze up. If he turns it off for a little while, it will turn back on and be fine again for a while. Sounds maybe heat-related?
He is the opposite of tech-savvy, so it's no use trying to get him to check the LEDs on the ROM board. He's also an hour-and-a-half away, so I'd like to go down with an idea of what to do when I'm there.
Anyone have an idea? Normally, my first inclinations would be either power supply/voltages, or RAM. What do y'all think?
The customer bought it from a shop a year or so ago (who didn't recap the monitor before selling it). The RAM had been upgraded to 4125's (with a trace cut) and the CPU had been modified to composite sync (with a trace cut). It also had a switcher installed, even though the original PS is still in there and has all the power LED's lit. It seems they left it to power the coin door and control panel lights. I also noticed that several of the ROMs had legs that broken off, and had clipped leads solder to them as replacement legs. Since the game seemed to be running fine, I didn't risk removing them to clean the legs, but maybe I should have.
Anyway, I noticed that touching the ribbon cable between the ROM and CPU boards caused the game to reset, so I replaced both ribbon cables with new ones. No more resetting when flexing the cables. I also reflowed all the connectors, fixed a bad wire to the volume pot, redid the monitor, installed new AA batteries, etc and everything was working fine.
Well, the customer called and told me that sometimes - after the game has been on for a while - it will either freeze while he is playing, or sometimes go to the rug screen and stay there. He tells me that when he first turns it on, it comes on just fine and plays fine. But if he leaves it on, later he'll come by and see the rug screen up. Or he'll start playing and it will freeze up. If he turns it off for a little while, it will turn back on and be fine again for a while. Sounds maybe heat-related?
He is the opposite of tech-savvy, so it's no use trying to get him to check the LEDs on the ROM board. He's also an hour-and-a-half away, so I'd like to go down with an idea of what to do when I'm there.
Anyone have an idea? Normally, my first inclinations would be either power supply/voltages, or RAM. What do y'all think?
