Discs of Tron (Bally Midway, 1983) (Page 3)

Repair

    First up, the list of things that need to be repaired (blue denotes done or partly done):

• Cabinet bottom edges need to be replaced/reworked. Water damage and age have made parts of the cabinet dangerously unstable. Removing the affected pieces and replacing them with new wood should help.

 
• T-molding needs to be replaced all around the cabinet. The stuff that is there is original, faded and cracked.

 
• Carpet lining the environmental section of the cabinet needs to be replaced with new, less ratty stuff. There's nothing worse for allergies than 18-year-old carpet that's never been cleaned.

 
• Front and back sections need to be joined, and the wiring between them connected. This may involve some repairs, since most of the sections that are to be joined will have been completely replaced and reworked beforehand.

 
• All lighting fixtures must be repaired or replaced, and blacklight bulbs need to be replaced. For the most part, this should be a matter of simply buying replacement bulbs, but at least one fixture is missing some key components.

 
• Wiring for coin door, volume controls, door lights, power supply, control panel and the speech board need to be brought up to code. There's too many splices, taped-up wires and potential shorts for stable operation of the game.

 
• Removal and replacement of reflective material on the sides of the cabinet above the control panel. The stuff that is there is bubbled, coming off, and generally ugly.

 
• Replacement of the game's monitor tube. The screen burn is too bad for me to live with, so out it goes!

 
• Repair of the light sequencer PCB and components for the lights above the monitor. The ones under the red plastic, they don't flash at all now.

 
• Removal of coin door and stripping of paint. Re-painting and replacement of coin door.

 
• Replacement of test switch. This is something I need to do to ALL my Midway games! The slide switch contacts are too corroded to make contact most of the time, and the switches are sealed as I recall.

 
• Replace control panel overlay and side art. Maybe someday someone will reproduce the artwork. I shouldn't have any problem peeling the old art off my environmental, the trick is keeping the stuff on that I have!

 
• Replace mirror reflecting monitor image. Mine has a series of pits along one portion of it, and it's a distracting eyesore. The trick is getting a new one that allows you to see through it to what's behind. I know a place that would probably be able to do it, but I imagine it's going to be EXPENSIVE, definitely over $50.

    First, here's an overview of the game's components:

The game consists of two pieces (in this case anyway): the main cabinet, and the environmental piece. The two interlock at the top and the bottom, and to a degree the sides at the top, and are held in place by several screws along the top. Due to water damage, the bottom is pretty rotten, and must be replaced before the two halves can be re-joined.
 
 

    The game has something like 5 fluorescent light fixtures (several of them are for blacklights). There is also an array of "flasher" lights above and in front of the player, behind red plastic art. Behind the game you find the on/off switch, another fluorescent light fixture (to illuminate the plastic backdrop), the game PCBs, power supply, transformers, and lots of wiring. The environmental Discs of Tron has 3 boards for the "main" game functions. The synthesized speech, which an upright DoT does not have, is generated by a separate board. Control of the flashing lights above the player, as well as the strobing of the fluorescent lamps, is accomplished by still more boards scattered around the inside of the game. As you can see, it is a much more complex set-up than you would find in your typical early-1980's arcade game.
 
 

    We spent a great deal of time trying to track down a problem with the flashing light arrays. At first, we could only get the middle light bulb (out of 5!) on each strip to light up and flash. Eventually, we puzzled out the method the game was using to get the lamps to come on - the PCB controlling it would send a ground to each lamp that was to be lit. By that time, we had already replaced the large capacitor on the sequencer board, and subjected it to a thorough cleaning/degreasing session. When I eventually get the game back in my possession, I'll remove some of the resistors and have them replaced with (working) better-quality pieces. Hopefully everything will work a bit better then.
 
 

          After mangling that portion of the game, we turned our attention to the speech synthesis: there was none! We thought it might have been set to only come out of the rear speakers in the enviro section, but that was not the case. All the connections on the board looked fine, except for the taped-up, half-broken wires on the plastic connector going to the squawk-n-talk board. I checked the schematics to make sure we had it wired up correctly, and discovered it appeared to be missing a ROM chip in position U2! The schematics showed there SHOULD be one there, but there plainly was not a chip in the socket, and none of the MAME ROM images for the game contained one for the U2 chip. Well, as it turns out, our problem was simple to resolved. The volume control for the speech is wired separately from the main volume control, and one of the wires to the speech volume pot (short for potentiometer, located inside the coin door, beneath the test switch) was not connected. A little solder later, Sark was threatening us with death :) "I don't know how you survived, SLAVE!" "Bring in the LOGIC PROBE!" "You'll regret this!!"

I love this game!
 
 

    My high score for the week was 103,700. Ed told me to keep hitting Sark so he could test different wiring and bulb configurations in the light sequencer, so I did!

    We worked on the enviro section a bit, but there really wasn't a lot we could do at the time, We stripped the ratty old carpet from the back (need to replace), and did some of the T-molding replacement. The majority of the T-molding on the back has to wait until the wood-work is done on the bottom portion of the main and enviro cabinet pieces. The replacement or repair of the side art is going to be a project all by itself! I was thinking of taking a hand scanner and making a faithful reproduction of all the cabinet art, but I'm not sure that's really going to be a viable option, financially. It will add to the value of the game, and to the ascetics, but I doubt I could get it reproduced for anything less than $300 per set. The reflective stuff on the insides of the cabinet should be simple to find a replacement for, but somewhat difficult to cut as it extends below the CP level, and has some odd angles because of this. The glue they used, by the way, is pretty tough stuff!
 
 

FINALLY, the wiring.. well, I'm going to have to do quite a bit of work to get that done, as I'll have to re-wire portions of the harness. The lighting fixture repair will be interesting, hopefully some kind person on rgvac will be able to assist in this when the time comes. For the moment, all restoration is on hold, except the wood-working, which Ed will take care of before he brings the game out to me.
 
 

Copyright 2001 Madoc Owain