Dig Dug Restoration by a Complete Noob

[SirPeale]

Is there any way of checking to see if the noise is being caused by the AR or the PCB or both? 

Paper towel roll to your ear.  Move it around.  When it's loudest, you have your culprit.

Rimshot!

And to think I almost ran upstairs to the kitchen to find said paper towel roll...

I'm beginning to wonder if I wouldn't be better off buying a GO7 monitor like what is supposed to be in the Dig Dug in the first place and finding a PCB that isn't jacked up as much as mine.  I can see a Dig Dug image burned into the monitor, but I'll be damned as to how they got an image to the monitor in the first place with the wiring the way it is now.  I've got a Joust project much further along than this Dig Dug project and I'm thinking about switching to that for awhile.

Erm...I was serious.  It's a common technique to find mystery noise locations.

I'm guessing someone just dumped that monitor into this game.  Like Kevin said, this monitor is setup to take 100VAC - MAX.  I'd measure the output of the isolation transformer to see if it's been replaced.

[Mauzy]

Wait: isn't the static and other bad sounds coming out of the cabinet speaker? I'd like to think I've followed this closely but perhaps I'm wrong. If that is the case the paper tube idea isn't really for this application.


Thats probably why PCP (hmm...never noticed that until I abbreviated his name...) thought Chad's idea was weird. I've used the paper towel tube method on a monitor in the past. Worked nicely.

[Pop Culture Portal]

Is there any way of checking to see if the noise is being caused by the AR or the PCB or both? 

Paper towel roll to your ear.  Move it around.  When it's loudest, you have your culprit.

Rimshot!

And to think I almost ran upstairs to the kitchen to find said paper towel roll...

I'm beginning to wonder if I wouldn't be better off buying a GO7 monitor like what is supposed to be in the Dig Dug in the first place and finding a PCB that isn't jacked up as much as mine.  I can see a Dig Dug image burned into the monitor, but I'll be damned as to how they got an image to the monitor in the first place with the wiring the way it is now.  I've got a Joust project much further along than this Dig Dug project and I'm thinking about switching to that for awhile.

Erm...I was serious.  It's a common technique to find mystery noise locations.

Seriously?  And I thought this was some weird initiation you were trying to put me through! 

And like Mauzy said, the noise is coming from the speaker, so I just jumped to conclusions that somebody was yanking my chain.  Sorry about that!

I'm on a business trip for a few days and I'll have to get back to my Dig Dug later.

[SirPeale]

I must have missed that.  I thought you couldn't tell if the noise was coming from the AR II or the monitor.

[Pop Culture Portal]

Those edge traces look like someone tried to repair them but didn't get it working.  Probably because the issue was the connector pin and not so much the edge contact.  So they bypassed it instead.  Weird route to take. 

If the connector pin needs to be replaced, which one should I get?

Also, just for the heck of it, I removed a few of the ROMs from the PCB and they look crispy.  I tried cleaning the edges with an eraser, but the black wouldn't seem to come off.  EDIT:  I mean RAMs,  not ROMs.  Also, how do I ID the type of RAM?  How do I know the difference between a Z80 or a 2016?

I count 6 caps on the PCB.  Would it be a good idea to replace those?

I also saw that the dip switches are cracked/broken.  Some of the switches won't even move.  Am I getting into the territory of just buying a working PCB at this point?  Would it be cheaper in the long run?

[Pop Culture Portal]

I've finally found a working GO7 monitor and replaced the EZ that was in the Dig Dug, but still no picture.  I do now have neck glow and a static sound when the machine is turned on.  I detached the speaker and the hum is now definitely coming from the PCB.  There is what looks like a red LCD light lit up on the PCB.  I accidentally rubbed up against one of the chips on the PCB while inside the cabinet and I actually thought it burned me it was so hot.  I carefully touched some of the others...some just as hot to the touch and others ice cold.

Any suggestions?
 

EDIT:  Here are some photo updates.


This shows still a stray monitor wire that appears to go nowhere.  Wonder if this is a hack that was done so the harness could be used with the EZ monitor that used to be in it?  You can see it in the bottom center of the picture.



This picture shows the PCB light that is lit up.  You can also see that I removed/unsoldered that odd wire sticking out of the PCB.

[Kevin Mullins]

I wouldn't worry about that connector coming off the monitor at the moment. It's not needed, but it's not hurting anything either.

Sounds like your game board is still dead.

Until you can coin it up and "play" a game.....looking at the monitor is pointless.
(unless it'll get into test mode at least)

[Level42]

That's not always so, board can appear dead but still put a static garble picture on. If fact that's what usually happens when the processor is not running.

[Pop Culture Portal]

What about replacing some of these chips on the PCB?  Some of them are clearly labeled as to what type they are and others just have a number on them that doesn't correspond to anything listed on Bob Roberts' pages.  And nothing I see on the schematics for the PCB match up with what Bob Roberts has either (this is a Rev. B Dig Dug board BTW).  I just noticed this morning that at least two of the chips are missing the little metal legs.  I suppose once I figure out which chips to get, then I'll have to figure out how to program some of them, I suppose.  I also know I should get a new connector for the harness to connect to the PCB.

[SirPeale]

Unless you're going to be doing a lot of PCB repair, it's probably worth your while to send the board to a pro.

Those 'hot' chips likely either have a short in them, or something around them is shorted killing the chip.

Check eBay as well...my Centipede was in the same boat, and I picked up a board there.

[Kevin Mullins]

I just noticed this morning that at least two of the chips are missing the little metal legs.  I suppose once I figure out which chips to get, then I'll have to figure out how to program some of them, I suppose. 

All depends on what kind of chip you are looking at.
What are the location numbers?

[rockin_rick]

I realize that this is really old and that the OP doesn't come on here much anymore, but for the sake of knowledge and for future searches, I'll add this...

I just started messing with my Dig Dug and mine has that same 20 EZY monitor in it.  My monitor has an Atari serial number sticker on it, which matches all the other serial numbers on the game.  The monitor is also mfg April 82, with the same ribbon cable coming off of it for the video input, and the short ribbon cable adapter harness connecting to the main harness, and has the 'normal' 6 + 3 .125 monitor connectors hanging down just like his was.  My guess is that the factory ran out of G07's and had to source a different one.  His serial number looks like it's #12638, mine's #13774.

And, of course, I don't have that silly 2 red wire harness thing soldered directly to my PCB...

FWIW

Rick