Tron reset circuit: fix or not?

BeagleBoy

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My Tron started booting to garbage this weekend, so I unhooked the purple line, and everything's fine.

So does anyone bother fixing the reset circuit on the power supply? Or do they just leave it disconnected?
 
Nine hours with no opinions? Who are you, and what have you done with KLOV?!

In all seriousness, I just verified that, indeed, my reset circuit is bad. I've seen at least one post claiming that Tron has "issues" if it doesn't get its reset. I'm an embedded software guy, so I can see how that could be an issue. But so far, I haven't noticed any anomalies.

So once again, ignore or fix?
 
I didn't reply earlier because this is such a basic question. It's like getting a check engine light on your car, and fixing it by putting electrical tape over the bulb.

Maybe the reset circuit is flagging a false-positive. Maybe the reset circuit is flagging an actual concern with the power supply. The smart thing to do would be to diagnose exactly why it's happening and repair that problem.
 
I didn't reply earlier because this is such a basic question. It's like getting a check engine light on your car, and fixing it by putting electrical tape over the bulb.

My voltages appear to be nice and stable, so it really does appear to be a failure in the reset circuitry itself. Plus, unlike a check-engine light, its purpose isn't to notify when power goes bad, but to send a single reset when power becomes good.

But unless a bunch of people post otherwise, I'll probably go ahead and fix it one of these days.
 
So lets say you just leave the reset line disconnected, Well it seems to run so what harm does can it do?

So the rest line doesn't trigger. Either defective reset line or something in the power supply is not working right to trigger the rest line.

I view little problems like these as little warning signs. Maybe one of the caps is drying out or there is something is on the borderline. Considering the cost of a bob roberts rebuild kit is 24 dollars, I would pop for it and fix the power supply. I tend to be safe than sorry when dealing with a power supply on an old and expensive tron board set.
 
It will run fine without it. Occasionally you may need to flip the switch a couple times to get it to boot correctly. If the rest of your power supply is healthy you shouldnt see any adverse affects from it.
 
Plus, unlike a check-engine light, its purpose isn't to notify when power goes bad, but to send a single reset when power becomes good.
That's not entirely true. From the MCR troubleshooting guide (link), section Reset Line: "This part of the Power Supply PCB provide a power-on-clear signal when the game is first turned on -- or -- after a momentary power line failure." Item B is the interesting one which explains "The pump charger circuit detects if two or more AC cycles have dropped out (AC line failure). Its output will go to logic 1 approximately 40 milliseconds after the line voltage starts to drop out." The circuit monitors power at all times and will reset the game any time there is unstable power: during first powerup, or during a brownout. So I think it's an appropriate analogy.

Obviously the circuit is overly sensitive -- lots of people have trouble with this, and the criteria of "2 low AC cycles" is pretty strict. But it's worth checking why the circuit decided your power is bad.
 
I agree with fixing it. I have fixed the one in my Tron using the MCR guide referenced above, and I still need to fix the one in my Spy Hunter. It was disabled at some point by removing the transistor at the end of the circuit that pulls the line (Q201). The guide explains clearly the purpose of each block, making troubleshooting a lot easier. It also includes reference o-scope signals at the end.

For what it's worth, R201 was bad on mine, causing the reference signal entering the opto-isolator to be crappy.
 
Rebuild and refresh all of it to new condition or get ready

To bring in the logic probe. Nice.

END OF LINE.
 
I am with Riptor, if your games is working, move on to another game. If this is the worst problem you have with your games right now, you need to pick up a project game! ;-)
 
I've got a cool project that I want to try with my Tron, but I'm missing my schematics (and the downloadable ones aren't legible-enough). So in the meantime, I'll probably go ahead and fix it.

Otherwise, at this very moment in time, my small collection of games is fully working.

Oops, I take it back: my dkjr doesn't have in-game music. I also have no desire to tackle that one right now.

-Jim
 
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