Tron - Fix tips

[guddler]

Can you guys share your Tron/MCR issues and fixes? Maybe need to start a new thread for that..

Nope. Fixed loads in the past but gave up logging stuff long, long ago as it takes too long.

Essentially these are no different to any other PCB stack. You need to have a good set of ribbon connectors that you can work with (I have a set somewhere to use when working on repairs). It IS possible to get RAM and ROM tests to work on a Fluke as I have done in the past but it's seriously, seriously picky about the speed and timing of the EPROMs that you use. The factory masked ROMs don't work with the Fluke for instance, or are at the least picky as anything to the point of seeming random.

Once you've got a known good set of ROMs and a known good set of ribbon cables then you're pretty well good to go.

The chokes can go up like chernobyl sometimes. Scary as hell when they do. If it happens, just replace the duff one with a wire link across the appropriate pads. They're only there for noise suppression and on a 25 year old PCB (30 nearly?) that's the least of your worries. When I asked my father about 10 years back, just before he retired if he had any, he just looked at me somewhat puzzled and said whenever they went in video recorders he only ever just removed them!!

What else? Oh, beware of "vanishing tracks". Don't trust your eyes!! (Or should that be TRUST your eyes?) I had a set once that I spent AGES going over and over and I just couldn't work out WTF was wrong with it, only to find in the end that a track literally dissolved into nothingness underneath a ROM (or some other socketed chip).

And finally, the reset circuit is a bugger. Go over the schems and make a note of every node that is touched by the reset circuit. You'll thank me for that sooner or later.

That's as much as I can remember for now.

[EDIT] One more - don't strive for perfection. You'll be wasting your time as theres quite a lot of bugs in the code for Tron. One immediately obvious one is if you don't have the buy in option enabled on the dips then in the event you don't get a high score the end game music will get cut off early. It's not a fault so don't bother trying to fix it, it's a code bug. And I forget off the top of my head but there's a bunch of stuff like that.

guddler2013-09-23 13:01:58

 

[DanP]

Only snippet I can think to add is that the game will run quite happily without the sound board attached so you only need to connect up the video and cpu boards to begin diagnosis/testing. Like Guddler I keep a set of cables just for testing.

Dan

 

[david_orton_2000]

Hi Martin and Dan,

Thanks very much indeed for all these tips - most appreciated!

I'll press on and either post here or on a new Tron repair thread.

Cheers,
DaveO.

 

[Judder]

Only snippet I can think to add is that the game will run quite happily without the sound board attached so you only need to connect up the video and cpu boards to begin diagnosis/testing. Like Guddler I keep a set of cables just for testing.

Dan

I never knew that Dan - that's gold-dust of information

What I can add is that Clay Cowgill wrote a Super-Sound I/O test ROM that means you can test the sound boards totally independently of the other boards.

All you need is power for the sound board, and a speaker output connected (*I've not tried this yet) and it will generate sound waves for you to test

Details and test ROM here

BTW how do you guys rig-up a test rig for the boards?

All the external board connectors are those fiddly pin rows so I'm guessing some sort of plug to Jamma affair as per the Williams conversions Dave L and others have done??