Dead Dig Dug

rikitheshadow

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Just picked up a dedicated Dig Dug machine that has issues. It has no video and screeching audio tearing through the speakers but no game sounds. So I ran a few checks...

Checked Atari Power Block Outputs and it appears within tolerance at 10.3 VDC where as needed. The Linear Power Supply however is outputting 4.7 VDC max (adjusted pot) or at least that is what I can get from the GND and +5v test points on the Dig Dug board.

I haven't tested the monitor any further than as to turn it on and confirm neckglow. All but one fuse was good and it only appeared to be the marquee lamp fuse.

I cleaned up a few contact prongs on the custom chips on the main board, but I think 2 of them had one broken prong.....others are weakening as well, but it had the same response before the 2 prongs broke.

Anyone know where to start with this? Is it easier to eliminate the old Linear Power Supply or is it a little more reliable than the Taitos? Can those chips be replaced or repaired?


I'm gonna post some pics of this cabinet later in general, but my camera is dead at the moment.
 
Just picked up a dedicated Dig Dug machine that has issues. It has no video and screeching audio tearing through the speakers but no game sounds. So I ran a few checks...

Checked Atari Power Block Outputs and it appears within tolerance at 10.3 VDC where as needed. The Linear Power Supply however is outputting 4.7 VDC max (adjusted pot) or at least that is what I can get from the GND and +5v test points on the Dig Dug board.

I haven't tested the monitor any further than as to turn it on and confirm neckglow. All but one fuse was good and it only appeared to be the marquee lamp fuse.

I cleaned up a few contact prongs on the custom chips on the main board, but I think 2 of them had one broken prong.....others are weakening as well, but it had the same response before the 2 prongs broke.

Anyone know where to start with this? Is it easier to eliminate the old Linear Power Supply or is it a little more reliable than the Taitos? Can those chips be replaced or repaired?


I'm gonna post some pics of this cabinet later in general, but my camera is dead at the moment.

The power supply is easy enough to fix and there is not much to em.

The chip can be repaired but you need a good to great soldering iron and good solder. I have sent some chips out to see how others repair the legs on the chips. I usually use an old non working chip for a donor leg. I clean the broken part with an xacto knife and then solder a leg to that chip. Many times I will put the chip into a socket I pulled from my Galaga boards (no pins) and put donor leg in socket and the replacement leg. This helps hold it all together while soldering and lining up.
 
The linear power supply in Atari games is usually very reliable. You should repair it. Once it's fixed, it'll work very well for a long time. Not only that, but putting a switcher in Dig Dug means that you'll have to use some other kind of mod to save the high scores. The EAROM needs a voltage that a switcher can't provide.

Click your meter over to the AC setting and see if you're getting a lot of ripple on the 10.3vdc line, and do the same with the 5v line. Inspect the edge connector on the game board, as well as the one on the harness. Dig Dug isn't as bad about this as other Atari games, but it can happen on any game.

You can diagnose and repair the ARII board, or you can just shotgun it with a rebuild kit from Bob.

The broken custom chips can be repaired. Individual legs, if broken off with enough stump left, can be fixed by clipping an entire leg off a junk chip, and soldering it on. To repair badly damaged custom chips, I solder them into a machine pin socket of the appropriate size, and then just make jumpers between the stubs of broken legs down to the socket. Then you can plug the whole socket/chip assembly into the socket on the board. To remove the black tarnish on customs, Tarn-X (silver tarnish remover) works great. You can dip the legs in a shallow pool of it, or use a q-tip to brush it on. Just be sure to clean afterward with alcohol to remove any Tarn-x residue.

-Ian
 
I have just used a piece of copper telephone wire, but I like the idea of using a donor leg.

It makes it fit in the socket a lot better than a round little piece of wire. That said, it can be more difficult to solder on a replacement leg than it is to use a piece of wire or a capacitor leg.

When I fix chips with a lot of broken legs, and solder them into machine pin sockets, I usually just use bits of cut off component leads as jumpers.

-Ian
 
Well from reading the test points on the ARII board +10.3 VDC reads pretty much on the dot not under load, but drops to +9.14 VDC whenever I plug in the game board. The +5 VDC test point on the game board still reads at a max of +4.7 VDC. Should I go for the Bob Roberts repair kit?

I'll get to working on the custom chips broken legs.........hopefully I can do it without messing something up. But those 2 larger custom chips by the edge connector I can't easily remove to clean, so I go to take a wack at those again.

Really would like to get this working myself, but may have to look into getting someone to do it for me if I can't get it running by fixing the bad chips.
 
Ok I ran some more tests after I cleaned up the bigger two custom chips. And then instead of using the game's monitor I plugged in a vga converter and pc monitor to get a look.
The signal jumps in and out, but I can see some color patterns similar to Dig Dug on the screen but nothing really else. It's like looking at orange fuzz.

So there has to be a sync issue somewhere and the game is resetting......

I tried a different power supply than the ARII and this time I had a steady video signal, but nothing on the screen but fuzzing dark boxes tracing everywhere. No orangish patterns like before.

I'm going to run more tests as soon as I fix all the custom chip legs.
 
If you can see very fuzzy blurred out things you can recognise from the game then its a video ground issue. If it was a sync issue you would not see anything you could recognise at all.
 
Ok, fixed up the custom chip legs. Now I have video signal strong enough to see something on the cabinet monitor. But its just a bunch or orange rectangles running across the screen.

If there is one thing I could fix it would be the ARII just because I can order a kit, but anything else I'm probably going to have to leave to someone else.

Now I know David Haney in Austin does Dig Dug repairs and provides warranty, but is there anyone else ya'll might suggest over him?


Edit: oh and here is a picture of the screen

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How about a pic of the board. I have one that doesn't look like the schematics. I will post pics of my board soon after the camera dries out.
 
Ok, fixed up the custom chip legs. Now I have video signal strong enough to see something on the cabinet monitor. But its just a bunch or orange rectangles running across the screen.

If there is one thing I could fix it would be the ARII just because I can order a kit, but anything else I'm probably going to have to leave to someone else.

Now I know David Haney in Austin does Dig Dug repairs and provides warranty, but is there anyone else ya'll might suggest over him?


Edit: oh and here is a picture of the screen

attachment.php

I have seen something like this before and I think this is a custom chip and possibly a clock issue. Verify all the sync chips and clock chips. The 07xx chip should have several different looking signals on most all of the pins.
 
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