Dig Dug Boots To Garbage ***SOLVED***

Sirsalt

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Not sure this is voltage related. I think so, but need some help confirming.

Dig Dug is running in my public arcade. Recently purchased, so I was waiting for it to die, or the monitor to take a dump. Most games aren't used to being on or played that much, and any problems show up in a week or two.

It froze while someone was playing. It stayed on the exact screen it froze on. Nice pretty Dig Dug scene. Stayed that way till I powered off.

On power up, the red LED on the PCB lights up and it boots to a static garbage screen. Sorry. Didn't get a pic of that.

I'm getting +5.1 on pins B, 2 and Y. +18.9 on pin 3 and and 14.5 on pin E.

The pin numbers/letters noted above coincide with the pinout pic. PCB and PS pics also included. Hope this is enough info.

Game was playing perfectly fine until freeze up yesterday.

Any help is appreciated.

-John

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I thought that 18.9v on the 36v line could be the prob.
 
By check eeproms you mean verify them with my eeprom programmer? No idea how to check the power on circuit. Any tips on how to do that?
 
Looking to purchase a replacement PCB so I can get this back up and running asap in the arcade. Based on the voltages I'm getting, are we sure power isn't an issue? Still wondering about the 18.9v on the 36v line. All the other voltages look good, except the 12v line being at 14v.

If the voltages are good, I'd like to buy a replacement PCB. Also interest in having the non working PCB repaired. With all the other things I have to work on at the arcade, and having a regular 9-5 job, I don't really have time to troubleshoot the PCB.

Thanks for any and all help.

-John
 
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By check eeproms you mean verify them with my eeprom programmer? No idea how to check the power on circuit. Any tips on how to do that?

If there's a reset button on the PCB, push that. If it boots, it's the power-on reset circuit.

Still wondering about the 18.9v on the 36v line.

This is AC, and you measured from one end to the center tap, so you read half the actual voltage. It's fine.
 
Try putting it into test mode, see if that generates any results. I'd also say to try re-seating all socketed chips.
 
Had limited time to work on it Sunday. Was only able to test voltages.

I'm gonna replace the big blue also. I was reading on Mike's Arcade and Arcadeshop that a faulty big blue can cause line wave, game freeze and 12v line measuring to high. All these are symptoms I'm having. The line wave actually started the same day the game froze.

Gonna install a new one and then do all of the other suggestions on this thread. Can't hurt to install a new big blue.
 
the way to test the Big Blue is to measure AC across +5 and ground. if its excessive it will cause the DC voltage to go low and high very rapidly and that will produce the symptom of low voltage conditions. it actually happens so fast you can't measure it as DC with your meter, but the game logic will know. :)
 
I'm not familiar with what's entailed in changing one of those. since it's a gigantic cap, that means it stores a lot of power. I don't know if you're supposed to discharge it first or not or if there's a way that you won't touch it together to make fireworks shoot out.

so, I'll be visiting this thread again later.
 
I changed the big blue in my Asteroids Deluxe without a problem.
 
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I'm not familiar with what's entailed in changing one of those. since it's a gigantic cap, that means it stores a lot of power. I don't know if you're supposed to discharge it first or not or if there's a way that you won't touch it together to make fireworks shoot out.

so, I'll be visiting this thread again later.

It's the filter cap for the 10.6V supply, so it doesn't store a charge that's going to do anything dangerous. Just unscrew the connectors from the terminals on the bottom, loosen the retaining band, and pull it out.

Pro tip: Instead of screwing around with all that just to find that it's not your problem, try this: Take two test leads with alligator clips on either end. Attach one between the + terminal of the new big blue and the +10.6V test lug on your AR board. Do the same between the - terminal and GND test loop. If your problem is fixed, it's the big blue in your power brick, otherwise it lies elsewhere.
 
Thanks for the tip. If I had to put money on it, I'd bet against it being the big blue. I've had a few probs with Atari games and the first thing everyone always says it to replace the big blue. It's never fixed the problem. The symptoms on my Dig Dug actually point to the big blue a little more than the other games I've done it to, so I figured what the hell, can't hurt.

I'm going to give the "test lug" tip a go before I change the BB. If I don't need to change it, I'll have one in stock just in case there's an issue down the road with one of my games.

I was also thinking about shotgun replacing the cpus. Only about $20 to do that. If it doesn't do the trick, I'll have a few Zilog 80's in stock as well. Not a bad thing.

Looks like ole Dig Dug may be down in the arcade this weekend.
 
this is seriously where a logic probe would be beneficial. easiest place to start is the reset line on the CPU. it should be high. pulsing means it's resetting (watchdog), low means it's not functioning at all. (or at least that's how I interpret this)

as with just about any old game, there could be a formation of corrosion on the legs of the chips. if they're anything but shiny silver, you have corrosion. Dig Dug being of Namco descent has custom chips (the solid black ones with a number in the corner) that have notoriously fragile legs, so cleaning them requires a lot of finesse. otherwise you'll be getting some practice time in fixing the legs you broke off. :) I've only ever sanded them, I guess that opens them up to additional corrosion again later, but even with the plating on them it happened in the first place, so what's the difference?

theoretically couldn't we just dip the things in CLR or something?

the other problem you can encounter is the sockets for the chips. I think Dig Dug had single wipe sockets, which aren't the bane of all evil like people make them out to be, but the way the pins are inside there's always a chance those could rust or corrode and snap right off. I've seen it a ton on Williams boards. obviously your socket is then hosed. the plastic housings for those lift right off, so you could open up the CPU sockets and just verify all the pins are uniform and intact too.

if the game was working before and now it isn't I would doubt that's the problem though. you have to physically move things around to break those.
 
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