Need some advice on trouble shooting TRON

slw74

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Please help me with me with a little diagnostic help or recommendations. I have a second board set for TRON which was sold "as is" on eBay. Here's what I've done so far and what's happening:

1. First power up with random screen items; L116 on SCPU smoked and ruptured. I replaced L116 and the 12 volt capacitors on the SSIO board. CP20 was shorted. I also replaced all of the 470 mf and 100 mf electrolytic capacitors on the boards; replaced the inter-board ribbon connectors.
2. Subsequently got a readable screen with a ROM ERROR D5; I took the D5 ROM from my working board set and replaced the defective one. Board booted to the start up screen. The game plays normally with two exceptions:
a. The left channel sound (Channels 4,5 and 6) are working, but are lower in volume than the right. I replaced the preamplifier (LM3900) without improvement. I am going to change out the sound generator chip and see if that helps.
b. All of the sprites (TRON, disc arm, tanks, MCP tower, grid bugs, cars) have horizontal lines through them in the color appropriate to each; see photo. I replaced both 2114-2 chips on the Vid Gen board along with all 8 of the 93422PC video ram chips with no change. Occasionally when I turn the game on, the sprites are OK for a couple of minutes.
3. I have intermittent loss of "UP" on the joystick with all other functions normal. That's not major for now.
4. The Vcc for both 5 volts and 12 volts at the chips are OK.

Please let me know your thoughts. Thanks again for any assistance that you can offer.
Thanks,
SLW74
 

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I had the same sound issue on my wacko a few weeks ago and cdjump told me to change the 3-4016s on the ssio. I pulled them, installed sockets (and new chips) and it fixed the problem. I don't know if that will help you, but it sounds very very similar.

You should pm cdjump about the sprite issue. He can either fix it for you, or possibly give you some advice.
 
my best guess for the lines on the sprites is a bad connection on the roms or rams or the sockets themselves looks like a leg isn't making connections somehow
 
Making progress on TRON!

I checked the eprom sockets and solder joints, all fine. I cleaned the chips and re-seated them with resolution of the sprite problems. All graphics are completely normal.

Thanks for your advice. I now have two complete, functioning TRON board sets.
SLW74
 
Making progress on TRON!

I failed to mention the volume difference on the left and right channels persists. Otherwise the sounds are all normal. I haven't gotten the 4016 chips yet.
Thanks, SLW74
 
I checked the eprom sockets and solder joints, all fine. I cleaned the chips and re-seated them with resolution of the sprite problems. All graphics are completely normal.

Could you clarify *which* chips you cleaned and re-seated. My Tron is behaving exactly the same way with sprites. (Audio is OK.)
 
I sound like a broken record, but a friends Tron had this double vision effect. I wound up tearing the boards down and pulling every socketed chip. I discovered a number of them were probably pulled in the past and reinserted with bent legs. the bent legs apparently make a difference with single wipe sockets cause I cleared that issue up doing the same thing.

I've had some Spy Hunters in the past with a lot of corrosion on the chips where they were either very messed up or wouldn't boot at all.

all in all, if ever in doubt, start checking socketed chips.
 
It'd be one of the eproms on the video pcb (back pcb in the stack) not making good connection causing the lines.

Could you clarify *which* chips you cleaned and re-seated. My Tron is behaving exactly the same way with sprites. (Audio is OK.)
 
When pulling ICs,I feel like it would be good practice to clean the legs and contact points. There seems to be some debate about DeOxit. Any thoughts?. Please forgive autocorrect or bizarre formatting.
 
Do you have access to an eprom reader/writer? I found my Tron PCB had a similar problem, I needed to reburn roms to fix my video problems. You could also swap roms from a working PCB with the same date stamps on the roms. I checked my rom chips with my GQ-4X. I made sure it was the correct set of rom images and found 3 or 4 roms were bad, erased them and rewrote a new rom file to the chips.
 
When pulling ICs,I feel like it would be good practice to clean the legs and contact points. There seems to be some debate about DeOxit. Any thoughts?. Please forgive autocorrect or bizarre formatting.

What debate is there about Deoxit? The stuff works incredibly well. There are different formulas/versions that you can purchase though so you have to watch which one you buy.
 
What debate is there about Deoxit? The stuff works incredibly well. There are different formulas/versions that you can purchase though so you have to watch which one you buy.
I thought I read something somewhere about it leaving residue or grease that attracts residue on your components.. Please forgive autocorrect or bizarre formatting.
 
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