Dig Dug Restoration by a Complete Noob

[Pop Culture Portal]

I'm really needing some help and hope you guys can hold my hand through the majority of this restoration as I am completely new at this.

I bought several games about a year ago and am just now getting around to working on some of them.  The Dig Dug that I bought for about $75 worked at one time according to the guy I bought it from.  He said he didn't have time to fix it.  Since it hasn't been hacked/converted into something else, everything appears to be intact.

I get it home, turn it on but there is no picture...only a gentle hum.  I figure it probably could use a cap kit.  I've read up on cap kits and am pretty confident that I can do it, including discharging the monitor.  I'm looking around inside the cabinet at the monitor and notice that there are several cracks/breaks in the monitor board where it is attached/screwed into the monitor chassis.  I can post pictures later if needed.

Now for the stupid question...do I need a new monitor for this poor machine or can I just replace the board?  It looks like it has a G07 monitor in it (I think).  If I get a new monitor, what would be the best kind for Dig Dig?

[Level42]

It just so happens that FrizzleFried has a working G07 chassis  for sale:

http://forum.arcadecontrols.com/index.php?topic=90183.0

Monitors are not game specific. (unless we're talking vectors or mid-res monitors) so you can swap them around at will (apart from the connectors that can be different of course).

I would get that chassis from the Frizz and be done with it.

[Pop Culture Portal]

Awesome!  PM sent to FrizzleFried.

[SirPeale]

Hold up...

Does the game play blind?  When you coin it up does it do anything at all?

[Pop Culture Portal]

Nope, nothing at all...coin door, marquee and the like light up, but nothing else.  It still has the "Big Blue" in it and I plan on changing that out soon as I get an order to Bob Roberts, but I don't know if that has anything to do with it. 

[ChadTower]

Big blue might eventually lead to a failure but a bad big blue alone isn't going to cause a boot failure.  You need to start by checking voltages off the transformer and at various test points up to the game PCB.  Make sure your PCB is getting proper voltages - won't play without them.

Have you checked the fuses?  Do you know how to use a multimeter?

[Pop Culture Portal]

Do you know how to use a multimeter?

Enough to be dangerous. 

I have a digital multimeter.  Should I set it to the continuity setting to test the fuses?  And which fuses do I test first?  I see them on the power supply and the monitor board...and what numbers are "good" when I read the multimeter?

And thanks for all the help.

[ChadTower]

Check the fuses on continuity.  There won't be a number, it will just beep which is good.  No beep is bad.  Order of testing fuses doesn't matter but be sure to pull them before testing.

Read this thread and the links inside it

And consider buying Randy Fromm's arcade repair videos.  They are worth the money if you have multiple cabs to repair.

[Pop Culture Portal]

I just looked at Randy Fromm's website the other night and those books are definitely something I should invest in...and thanks ChadTower for the thread link!

OK, I've tested all the fuses I see...6 on the power supply and one on the video board (shouldn't there be two?).  All fuses "beeped."

Also, there's no sound coming from the game.  I also read somewhere that the neck on the monitor is supposed to "glow."  I don't see any kind of glow on this monitor.

[Level42]

Order of testing fuses doesn't matter but be sure to pull them before testing.

No, no, no, checking fuses is done WITH NO POWER CONNECTED, but at the fuse _holders_.

This way, you will also know if the contact between fuse and fuseholder is OK.

[Pop Culture Portal]

Order of testing fuses doesn't matter but be sure to pull them before testing.

No, no, no, checking fuses is done WITH NO POWER CONNECTED, but at the fuse _holders_.

This way, you will also know if the contact between fuse and fuseholder is OK.

Gotcha...all fuses still beep while in the holder.

Does anyone have a picture/guide as to how the harness connects into the monitor?

EDIT:  Damn...this is a Sanyo 20-EZY monitor, not a GO7.  It says on the chassis:

MODEL NO. 20 EZY
MANUFACTURED APRIL 1982
CRT TYPE
51OUTB22

[Level42]

Great monitor IMHO but I bet the G07 chassis won't work on that one.

We _are_ talking about an Atari Dig Dug right ? If so probably not factory.

[Pop Culture Portal]

Yup, Atari Dig Dug...I'll post lots of pictures momentarily.

I can always use spare parts like the GO7.

[ChadTower]

No, no, no, checking fuses is done WITH NO POWER CONNECTED, but at the fuse _holders_.

This way, you will also know if the contact between fuse and fuseholder is OK.

You can get false positives checking fuses still in the circuit.

[Pop Culture Portal]

No, no, no, checking fuses is done WITH NO POWER CONNECTED, but at the fuse _holders_.

This way, you will also know if the contact between fuse and fuseholder is OK.

You can get false positives checking fuses still in the circuit.

I actually did it both ways and got "beeps" all around.  Finally the photos:

The monitor:



Cracks in the monitor board can be seen in the upper corner:



There are four dangling wires not connected to anything, but I don't see where they might go.  One looks like a ground wire, two are coming off of the monitor wires/harness, and the fourth is a wire coming directly from the PCB.  The red wire from the PCB can be seen in the second picture near the top right of the picture:





Do these help?

[ChadTower]

The dangling connectors are your video signal wires... they would attach to the monitor chassis.

[Pop Culture Portal]

The dangling connectors are your video signal wires... they would attach to the monitor chassis.

Holy smokes...

Well, I AM new at this.  I plead ignorance!

I still don't see any place for them to "plug in" to the chassis.

[Mauzy]

The dangling connectors are your video signal wires... they would attach to the monitor chassis.

Holy smokes...

Well, I AM new at this.  I plead ignorance!

I still don't see any place for them to "plug in" to the chassis.

Heh-we're all new once.   

If you can't find it, post a picture on as much of the board as you can fit in a component-side shot (i.e. the "top" of the board) and we can help you find that connector. Needless to say, that is a very important connection!

As for that corner break, you need to make sure no contacts on the bottom of that board are shorting to the metal frame. A rubber spacer is probably a good idea in this situation.

[Pop Culture Portal]

Hopefully these are good enough...

[Mauzy]

Oh wow thats...strange. I can't seem to find the input either. Maybe someone else on here can - maybe Chad has better eyes than me. If you still can't find it after a day or so, post it over in the monitor forum. Surely someone over there knows where to find it.

[Pop Culture Portal]

Yeah, I'm assuming I'm looking for male input "parts" since the dangling wires have female plugs...really weird.

EDIT:  Added a topic over at the Monitor threads...

[Mauzy]

Exactly. Usually it sticks out like a sore thumb. Maybe you're missing something. Honestly, I've never seen this monitor before.

[Kevin Mullins]

That's a version of the Sanyo that does not have the inversion board. (which I don't believe you need by the looks of the chassis configuration)

The video input is marked with green arrows, follow that bundle of white wires back down towards the game pcb and show us what you have going on there.
It should all be tied in together with those dangling loose wires somehow. Those are a standard style connection, but that particular monitor does not accept them directly.

As for the monitor itself.....
Do you hear the static startup?
Does the neck of the tube have any glow?

[Pop Culture Portal]

Here are close-ups of the wires:







There are actually two green wires; one goes to the PCB and the other goes to one of the disconnected female plugs (the larger of the two) that you can see in the first picture.

In the second picture, you can see the green wire go into the connection for the PCB.  You can also see the red wire with a male plug coming out directly from the PCB.

The third picture just shows the PCB and the harness attached to it.  The green wire ends there.

I hear no sound (except for the marquee light coming on) when the machine is turned on...no crackling, no humming.  And I'm assuming the neck glow would be obvious...I don't see anything glowing.

[Kevin Mullins]

I'm assuming the connectors I circled in green are tied into the connector I circled in red somehow.
Is that correct?

You need to check for AC power at the connector I pointed at with the red arrow.
That is what feeds the monitor power.
If the power is good there, then you'll have to move into the monitor repair side of things.
(and of course check for any fuses in the bottom of the cabinet as well if it's not good)

[Level42]

No, no, no, checking fuses is done WITH NO POWER CONNECTED, but at the fuse _holders_.

This way, you will also know if the contact between fuse and fuseholder is OK.

You can get false positives checking fuses still in the circuit.

Very rare. That's also why I use Ohms and not the continuity setting.

[ChadTower]

Very rare. That's also why I use Ohms and not the continuity setting.

My experience has been different.  It's not common but it can happen and it takes two seconds to pull a fuse.  It happens a lot more in pinball machines I've noticed with so many more fuses and more fuses on PCBs.  Here is a decent discussion on the idea.

I'm not familiar with this monitor... could he be missing a signal PCB and that's where the game signals would go?

[Pop Culture Portal]

I'm assuming the connectors I circled in green are tied into the connector I circled in red somehow.
Is that correct?

You need to check for AC power at the connector I pointed at with the red arrow.
That is what feeds the monitor power.
If the power is good there, then you'll have to move into the monitor repair side of things.
(and of course check for any fuses in the bottom of the cabinet as well if it's not good)

The connectors circled in green go directly to the connector in red.

I checked the AC power at the connector with the red arrow and I'm getting a reading of 1.048.  Does that seem right?  I also check all the fuses at the power supply and they are all good.

[Neverending Project]

The connectors circled in green go directly to the connector in red.

I checked the AC power at the connector with the red arrow and I'm getting a reading of 1.048.  Does that seem right?  I also check all the fuses at the power supply and they are all good.

Make sure your multimeter is set to AC Voltage. The reading you say was probably either Resistance or DC Voltage.

[Pop Culture Portal]

The connectors circled in green go directly to the connector in red.

I checked the AC power at the connector with the red arrow and I'm getting a reading of 1.048.  Does that seem right?  I also check all the fuses at the power supply and they are all good.

Make sure your multimeter is set to AC Voltage. The reading you say was probably either Resistance or DC Voltage.

Oops!  It was on DC...now it reads 120.

[Kevin Mullins]

...now it reads 120.

And you are sure there is no neck glow ?

[Pop Culture Portal]

...now it reads 120.

And you are sure there is no neck glow ?

Nope, nothing even flickering.

[ChadTower]

The connectors circled in green go directly to the connector in red.

I checked the AC power at the connector with the red arrow and I'm getting a reading of 1.048.  Does that seem right?  I also check all the fuses at the power supply and they are all good.

Make sure your multimeter is set to AC Voltage. The reading you say was probably either Resistance or DC Voltage.

OTOH, now we know his big blue is decent, since we know he has very little AC ripple.   

[Kevin Mullins]

Does the game play blind?  When you coin it up does it do anything at all?

Nope, nothing at all...coin door, marquee and the like light up, but nothing else. 

That's another thing to dig into.... gotta have it playing (at least blind/no monitor) in order to troubleshoot clearly.

[Kevin Mullins]

...now it reads 120.

And you are sure there is no neck glow ?

Nope, nothing even flickering.

Then the monitor is not even firing up for sure.
Would start by capping it at the least.......hopefully you won't have a dead flyback.

[Kevin Mullins]

OTOH, now we know his big blue is decent, since we know he has very little AC ripple.   

Yup, time for him to break out the schematics and check voltages at the board and coming from the ARII board.

Is there anything noticeably burnt up on the ARII board? (namely resistors)
It's the small board mounted under the main board with the big heatsink.

[ChadTower]

And make sure you even have the right AR board - that could easily be one someone just threw in there to say the game is complete.

[Pop Culture Portal]

Here's what I see and honestly it doesn't look right.







Notice in the second picture the wrinkled look of the back of the AR board.

In the third picture, I see day-glo orange marshmallow-cream consistent "junk."  I'm assuming that's not good, either.

[ChadTower]

The wrinkled look is normal - the copper traces do separate some over time.  As long as they are intact you're fine.

The orange goo is probably glue.  Heavier components often get glued to the board to stop them from breaking off.  Why they would glue one but not the other, who knows.

You're going to want to rebuild that whole AR board anyway so you'll be replacing all of those capacitors.

[SirPeale]

If that's a Sanyo monitor, the connector on is is very tiny and you won't be able to use the Sanyo anyway.  Couple that with the missing inverter board, and you're double screwed.

Looks to me like that monitor was just tossed in there.

And note the ground wire soldered directly to the PCB.  Check the harness, was it clipped there too?

[Pop Culture Portal]

Something was clipped from the harness at the connector for the PCB (does that make sense?) but I can't tell what color the wires that were clipped were.

Also, there is a number on the AR board that says "1160697-01."  Am I right in assuming this is an AR II-01 board and that's the kind kit I need to rebuild that board?

[ChadTower]

http://www.therealbobroberts.net/parts.html#atari

First check the manual to make sure that's the right one.  It may not be.

[Pop Culture Portal]

Yup, the manual says A/R II.  And I see all the caps and the Q2, Q3, and R29 on the board that Bob Roberts lists in his kit (Atari A/R or A/R II-01 Repair Kit (Caps+Q2/3+R29)).

So, doing a little research it looks like these Sanyos were for Nintendo games?  Should I just buy a refurb'd GO7 like what was supposed to be in there in the first place?

[ChadTower]

There are a bunch of monitors you could get but the G07 is as good as any I suppose.  Local is always best with this stuff if you have anyone around.  Here is a good baseline price.  That's retail, keep in mind, so it would be lower from a random person.

[Kevin Mullins]

If that's a Sanyo monitor, the connector on is is very tiny and you won't be able to use the Sanyo anyway.  Couple that with the missing inverter board, and you're double screwed.

That's why it looks like the video has been tied together into that larger molex to me.
Actually has two options now, the Sanyo setup AND the standard setup for more common monitors.

I pretty certain he doesn't need the inverter board because the chassis has the triple set of transistors and resistors that is normally "missing" in a Nintendo version. The Sanyo actually started out as "normal" monitors, they were modified to work with the Nintendo which they are more commonly found in. The inverter board is there to make the "modified" versions work with standard games.

[Kevin Mullins]

That is the correct ARII board for Dig Dug.

Hard to really tell in the pics, but check all the resistors closely and with a meter to see if any are open (burnt/broke). Especially like R29, R30 I believe.
That pcb edge connection already looks like it's has some soldering repairs done to it on the main board, so I would double check for good solid connection with the wiring harness plugged in. That will cause those resistors to burn up that I mentioned and you will loose voltage going to the game board.

[Level42]

Yep. Shame it's missing, I could have used one

Seriously, if you can get the Sanyo working, it will be a great monitor. Off all my cabs the Sanyo (not 20EZ, earlier version) in my Nintendo cab is by far the best looking of all of them. And yes it has been running quite a bit because there is a slight Radar Scope burn-in AND I haven't even re-capped it (except for the fold-over cap). And even so, the picture is like new. Ask Polaris he saw it yesterday and was amazed

[Kevin Mullins]

And note the ground wire soldered directly to the PCB.  Check the harness, was it clipped there too?

Yeah, I saw that too, but didn't see anything for it to plug into in the cabinet.
Maybe that was a quick fix by someone because the edge connection was bad.
It definitely appears that the edge has been repaired or at least has something going on there. But the original wiring still appears to be in the harness correctly. And the spots that look "odd" are obviously power/ground related.
 

Can you get a decent picture of that pcb edge connection without the harness plugged in?
Maybe we can see something going on there as well.

[Kevin Mullins]

Yep. Shame it's missing

What I'm saying is it's not "missing" .... it was never there. 

And yes, these are damn good monitors when working.
As long as the flyback doesn't go out.....it'll last and look good forever.

[ChadTower]

Well, those Atari games are known for having truly crappy connectors... and it doesn't look burned... so someone probably just bypassed the connector rather than repin it.  At least they put a molex on it so you can still remove the PCB.

[Kevin Mullins]

Yeah, I just don't see the other end of it hanging around anywhere.
(not in any of those pics anyways)

[ChadTower]

I guess it would be in the harness... unless they did it outside the harness going back to the AR board and they didn't put the other half back in.  Either way that should be a fairly straightforward thing to undo by repairing the original connector.

[Kevin Mullins]

Agreed.

Which is why I was asking for a good pic of the pcb edge...... just to see what shape it's in at the moment.

You know how it goes... one guy does one thing, another comes behind and does something else, then who knows where it came from and what's been done in between.
Heck, someone may have repaired the edge and was just too lazy to undo the other guys stuff.
Seen it happen all too often, working on a bunch of those right now as a matter of fact. (what a mess)
 

[Pop Culture Portal]

My camera is suddenly on the fritz so I tried some scans instead.  I may need to find my wife's camera...

[ChadTower]

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. 

[Kevin Mullins]

I have had to do similar repairs before by repairing a break and then "tinning" the edge connector, but why they didn't tin the entire trace all the way out I don't understand.
That ground trace looks especially questionable, which might explain the red wire adapter thing.
Clean them all off real good with something gentle like a pencil eraser and see how they look then.

And like Chad said..... it probably has some issues on the harness connector as well.
Check for charred blackened tarnished pins and such.
Make sure they all fit tight, the gap between two opposite pins should all be equally narrow.

Also let us know how them ARII board resistors look.

[ChadTower]

I've done a bunch of those Atari connectors... sometimes they don't look that bad but have come loose in the crimp.  Or you can't tell the tin has snapped because the break is out of line of sight.

[Kevin Mullins]

I know what you mean.
I like to ohm them from the game pcb all the way to the ARII and whatnot and if they are even questionable I redo them.

[Pop Culture Portal]

Damn...I just stepped on my multimeter and broke it.   

I gotta move this stuff out to the garage where there's more room.  Well, off to Lowe's.

[Level42]

Hey, it is friday the 13th. First the camera, now the multimeter. ....

The connector was still great looking on my Missile Command cabaret BUT it had very loose tension on the board edge and following it it had burned the resisitor on the AR2. Luckely an easy fix.

This video gives you an idea how an old connector compares to a brand new one (please excuse my English ):

[ChadTower]

Your English is as good as half the people I work with.  And they're American born.

One thing, though... bad contact doesn't increase voltage, it increases heat, through reduced material for the same current to pass through.  Increased heat burns it smaller, which makes it hotter, which burns it more... until it's fried.   

[Level42]

Thanks.

Yeah, maybe should have written a text before filming that The funny thing of it is that I had only one hand to handle the connectors, and the first time I take off the original one it really pops loose right away. More or less accidently but it really shows how poor the tension has become.

What I actually meant is that the AR-II will increase the voltage because it will "think" the voltage is too low because of the bad contacts.

Hey, I am educated in electronics, if there's one thing I should know is that U=I x R   

In essence they should have used separate connectors for the power connection. One's that are designed to carry more current. Williams made the same mistake with their connectors. But hey, they didn't design those machines to last 25 years

[Pop Culture Portal]

My God, yesterday WAS Friday the 13th!

Well, got a new multimeter and checked the resistors on the AR and 12 of them are bad (I wrote down which ones didn't beep at me).

Can I check the capacitors with the multimeter?

[ChadTower]

That's not how you check resistors... you need to look up the value and check it with the Ohms setting. 

You can't really check the caps with the multimeter.  Assume they are bad and replace them because electrolytic caps have a relatively short lifespan. 

[SirPeale]

You absolutely can not check resistors with continuity check.  It must be done with the ohms setting on your multimeter.  A lot of resistors don't pass enough electrons to allow the continuity check to beep.  If any of the resistors are going to be bad, it'll be R29 or R30.  If they're not burned, they're probably okay.

Chad is right, you should replace every electrolytic cap on the board. 

[Pop Culture Portal]

Man I've got alot to learn...

OK, here's the readings I get for each resistor:

R10 (1 Ohm +/- 5%) - reads 1
R19 (1 Ohm +/- 5%) - reads 1
R11 (10 Ohm +/- 5%) - reads 9.9
R20 (10 Ohm +/- 5%) - reads 9.7
R29 (10 Ohm +/- 5%) - reads 11.2
R30 (10 Ohm +/- 5%) - reads 12.3
R4 (100 Ohm +/- 5%) - reads 99.3
R12 (100 Ohm +/- 5%) - reads 99
R22 (100 Ohm +/- 5%) - reads 99.2
R27 (1k Ohm +/- 5%) - reads .988
R28 (1k Ohm +/- 5%) - reads .994
R13 (10k Ohm +/- 5%) - reads 9.92
R14 (10k Ohm +/- 5%) - reads 9.92
R1 (270 Ohm +/- 5%) - reads .265
R3 (33 Ohm +/- 5%) - reads 32.8
R6 (3.9k Ohm +/- 5%) - reads 2.69
R7 (7.5k Ohm +/- 5%) - reads 3.09
R9 (220 Ohm +/- 5%) - reads .202
R21 (220 Ohm +/- 5%) - reads .218
R5 (2.7 Ohm +/- 5%) - reads 2.7
R24 (.1 Ohm +/- 3%) - reads .1
R8 (1k Ohm) - reads 1 (I'm not sure if I checked this one correctly)

If I'm doing it right this time, it looks like R6, R7 and R9 aren't within the +/- 5% range and should be replaced.  Is that right?

[SirPeale]

Did you get these values from the schematic, or from the resistors themselves?

I'd be less concerned with the values of the resistors and more concerned with the output the AR/II is putting out.  Measure this AFTER recapping, however.  But if you're really concerned, replace away.

[Pop Culture Portal]

Yup, all the values came from the schematic book.  Think I'll recap first before replacing any of those resistors.  Cap kit for the AR has been ordered from Bob Roberts.  Now for the wait.

[Level42]

Those values look OK to me. I assume that you've measured across the resistors in circuit (without soldering one end loose). What you will measure then is not only that resistor but (depending on how it is positioned in the circuit) also other parts that may be in parallel with it.

As you can see, most values are very close though. Some of the others are a bit more off because of that reason probably so don't worry about it.

If you really want to accurately measure a resistance you will have to solder one leg loose, lift it up and then measure it.

However, I really don't think there's a need to do that. Like Peale says, the only often failing resistor is R29/R30 and it's because of it's "position" in the circuit.

Replacing the caps is something you should do as a precaution, but I don't think the real problem is there. It's more likely that one of the transistors has gone.

If you ordered the full repair kit for the AR-II and replace all parts, there's a _very_ big chance it will be OK again.

See some AR-II work I did on my Missile Command here:
http://forum.arcadecontrols.com/index.php?topic=81554.msg865768#msg865768
That was actually the only AR-II that I've had failing.

I assume you also ordered a cap-kit for the monitor while ordering from Bob ??

[Pop Culture Portal]

Yes, I did measure in circuit and I did remember to order the monitor cap kit (at the last moment!).

[gameguy1957]

Once you get the voltages correct and everything appears to be right so that is should be playing blind, but it doesn't, check the volume pot. It may actually be playing blind, but you just can't hear it.

Same on the monitor, once you get a neck glow and replaced the caps, be sure to check the brightness if it still doesn't get a picture.

You'd think things like that would be obvious, but I recently picked up a 'dead' game cheap and the only problem was that both the sound and brightness were turned all of the way down.

-JM

[Pop Culture Portal]

Finally got around to installing the AR kit and I now have sound...but it's kind of a combination of static and a loud whistle.  Now on to the cap kit for the monitor...

EDIT:  And both the Player 1 and Player 2 buttons stay lit...that didn't happen before. 

[Level42]

Is your 5V output on the AR-2 still OK after the cap-kit ? Sounds like your board is hanging.

[Pop Culture Portal]

I touched up the solder on the cap kit I installed and added a little more to the 5v.  The whistle is gone, but I still have a large static sound, like trying to get a channel on an old TV and the signal just isn't quite strong enough.

[Kevin Mullins]

EDIT:  And both the Player 1 and Player 2 buttons stay lit...that didn't happen before. 

Player buttons staying lit solid (not blinking) is an indication of an error on the game board.
Have you tried to get into test mode since the AR kit?

You may also want to carefully re-seat any socketed chips and connectors going to the game board.

[Level42]

I touched up the solder on the cap kit I installed and added a little more to the 5v. 

How much little more did you add to the 5V ? Measure between the test-points on the game PCB between GND and 5V. Get it as close as possible to 5.00V there.

[Pop Culture Portal]

I touched up the solder on the cap kit I installed and added a little more to the 5v. 

How much little more did you add to the 5V ? Measure between the test-points on the game PCB between GND and 5V. Get it as close as possible to 5.00V there.

Another idiot question...I used the multimeter and found the GND and 5V points on the PCB and tested between the two and got a reading of 5.0 (if I did it right).

I just installed the cap kit for the monitor and there is no change.  I did notice that one of the caps on the monitor board had been snapped off.  I had hoped that putting a fresh, new cap in that spot would help in some way, but it didn't.  Still no neck glow and I did check the brightness to make sure it wasn't turned all the way down, but that doesn't seem to be my problem.

Is there any way of checking to see if the noise is being caused by the AR or the PCB or both?  I went back to make sure I installed the AR Repair Kit correctly and it looks like I did...polarity is right, correct caps/resistors.  What should I try next?

[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.

[Kevin Mullins]

Starting to wonder if by sending 120v to that monitor has damaged other components. It's typically a 100v monitor.
Might want to start checking all the major transistor like the H.O.T. and the measure the B+ to see what it's doing.

[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.

[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