Tron Restoration - Power Supply Headaches

Started working on my Tron a couple weeks ago. The first thing I needed to do is to make sure the board worked. I ran over to jsquared’s house (another collector in South Bend) to try it out in his cabinet. The board powered up to the Tron logo, but locked up when selecting a level. This was much better than I was able to get it to do from my cabinet, so I decided I’d better get the power working right first. Then, I could troubleshoot the board.

The board had some severe battery corrosion damage to it. Many of the components were corroded and just as many traces on the power supply board were ruined. I decided that I would try to rebuild and repair the board using Bob Roberts’ MCR Power Supply Repair Kit. I’ve actually used one of these before on my old Kick cabinet and it worked great. The trouble is, it is very time consuming and some of the components you replace through the kit are very hard to remove from the board. Basically this kit is designed to replace just about every component on the board that can fail. Replace all of these parts, repair any damaged traces on the board, and you’re good to go! So I hoped this time…

Got the parts in, and started working on it. I spent about four hours replacing parts and repairing traces. Each time I tried the board out in the cabinet, it would just be dead. Further digging led me to even more traces farther away from the corrosion that were also effected. Finally, I go the board to do something, but it ended up just looking like it did when I brought the game home.

here are some pictures of what I did:

The parts are in from Bob Roberts!

Before the repair.

Some closeups of the damage…

Here’s what’s under the 9 pin molex connector. This one was really bad!

The pins in one of the molex connectors before replacement.

This is after I yanked the battery out.

The voltage adjustment pots were really bad. Wouldn’t even turn.

All done! Does it work?

The resulting carnage!

I then decided to call for help! I posted a tech question on the KLOV Forums Repair and Help message board, and received quite a bit of help recommending that I cut the reset wire. From what I was told, this was a common problem with this game, and that the reset wire wasn’t really needed. It was used to reset the game if power issues were detected to prevent damaging the main boards. I really hoped this would work, but nothing changed…

Finally, one of the other suggestions I received was to purchase a Switching Power Supply adapter. There is a special adapter for games in the Midway MCR platform to replace these difficult power supplies. I decided that I would give this a go. After wiring it in and fixing a couple main AC wires that were loose, I got the cabinet to power up to the same state that I saw over at jsquared’s.

This was a ton of work just to get this far! I’m glad I’ve made some progress. Now the tough work begins, diagnosing the board and fixing the current issues with it. Basically I have a couple issues I can determine. First, I get a “Sound Interface Error”, which leads me to believe that the sound board does not work in the PCB set. Second, the game still locks up once you try to select a level. Actually you don’t even see the sprite used to make the selection. You can still make an attempt to select the level, but it immediately locks up. I can boot to the diagnostics menu, and even select different tests, but still don’t see the selection sprite. The sound test of course does not work, and exiting the controls test by hitting the Tilt switch locks the game up. Other than that, the tests seem to complete. I think the first thing I need to do from here is replace the ribbon cables that connect the boards together. These are no longer available, but Bob Roberts has some short SCSI cables that can be used to replace these. They’re pricey, so I may just try to fix what I have.

I’ll take some pictures of my current status, and maybe a video, as soon as I get a chance this week.