Dig Dug. I must be going crazy.

[nulogix]

I think I'm going crazy. Restoring a dig dug.

Power brick rebuilt. Tested and got good readings. 15.4v DC, 37.6v AC, 6.1v AC.

AR2 tested. 14.69v DC at 10.3v DC test point. 5.06v DC coming out of J7. Plugged in harness.

Tested edge connector, correct voltage at the right pinouts.

Plugged in and powered on the board (supposed to be a working board). LED comes on. No smoke. Whew.

+5v test point shows 4.96v. 10.6v test point 12.02v. Power off.

Go eat dinner. Come back.

Get a spare dig dug harness. Check it as well. All readings correct. This one has a key to prevent plugging it in backwards.

Power on. LED comes on but is blinking. Power off immediately. No smoke. Unplug everything, start from scratch. Check all voltages again starting with power brick. Same readings. Plug everything back together. Double check correct, then check again.

Power on. LED blinks 3 or 4 times then goes completely out. Power off. Check everything is correct and power on. No LED.

Put back on first harness, check voltages, looks ok. Power on and no LED. Check voltages on the board. +10.3v shows 12.1. +5v shows basically nothing, 0.63v.

Check the pin in the edge connector, still getting 5.06v. I check voltage on the big trace that comes out of the edge connector. You would think if I had a short I would still get something there, right? That reads 0.64. I checked all the 5v pins on the ICs and they were all 0.63.

I used a multimeter and still get continuity to all the 5v pins on all the ICs with the 5v edge.

Thoughts? I'm going crazy.

 

[andrewb]

Check the pins in your edge connector. Check edge connector fingers on the game board for any damage. If the 5V and/or GND pins have any signs of burn or browning, they'll need to be cleaned.

Make sure you don't have any breaks in your harness, between the AR and the game board. That includes the 5V and the GND wiring.

If you have another AR-II (any type), you can swap it out, to see if the AR is the issue.

Also, use the positive side of the C1 cap to determine what the 5V at the AR is. Make sure you're checking the correct pin, if you're measuring at the harness edge connector for the game board. If you have 5V at the back of the edge connector (where the wire goes into it), you should have 5V on the board. Else you have a broken pin, wire, or some other issue with the edge connector itself.

Did you replace the 2N3055 bottlecap transistor on your AR? If not, you should anyway, as they all have high hours on them, and can fail and fry your board. They can also fail in ways that give 5V with no load, then they'll tank with a load. Get one from Digikey, Mouser, or ArcadePartsAndRepair.com. Not ebay, Aliexpress, or any other small parts sellers, as there are a lot of fakes out there, even from arcade parts folks.

 

[nulogix]

Did you replace the 2N3055 bottlecap transistor on your AR?

It was this one by gcpowers: https://forums.arcade-museum.com/showthread.php?t=452226

So, this has been rebuilt.

 

[nulogix]

Dig dug

Here are the readings at the edge connector.

 

[nulogix]

Here is measuring at the trace.

I get 0.6 at the 5v trace and 12.2 at the 10.6v trace.

 

[andrewb]

In your pics, you're measuring at the edge connector with no load on the AR (basically into an open circuit). Then you're measuring on the board with the board connected, which presents a load to the AR. These are different conditions.

All of the behavior you're describing is consistent with a bad 2N3055 (i.e., measures ok without load, ~0.5V with load, and it worked for a few hours when you got it, and then changed without you touching anything).

My guess is the 3055 he used is a fake (or just bad), as that's exactly how they behave, in that they last a few hours to days and then crap out. It also has no marks indicating what manufacturer it came from (not that that will guarantee anything, as people fake the marks as well. But that one shows none of the major brands.)

Replace it and see where that gets you. It could be the LM305 as well, but my money is on the 3055. Paypal me six bucks and I'll send you one.

 

[nulogix]

Andrewb, pardon my French, but you're a smart motherf#@%er.

All I did was put a different ar in.

 

[andrewb]

Nice. Yes, I've just spent a lot of time with these.

BTW, the nuts are missing on that 2N3055 on the other AR. It might not be held tight to the heatsink, which you sorta need, as a lot of heat needs to get from that part into the sink.

You should fix that, else you're likely to overheat the part and blow that AR as well. However you don't just want to put nuts on there and crank down, as that will stress the solder joints below it.

The right thing to do would be to remove the solder from the two pins on the back, remove the 3055, inspect the holes, then reinstall the part with the nuts, tighten it down, then resolder it in. If you just crank down on some nuts without desoldering, you could risk cracking the solder joints.

If you want to trade both of those AR's in for a proper AR-II-01 for that machine, let me know. I have properly rebuilt ones.

 

[nulogix]

The working one is from my centipede/millipede. But I could trade the other one. What would be the damage (cost)?

Sort of related. I have a galaga board that I'm trying to repair. I don't have a good board to see which customs do and don't work.

I got it as "working" but it had a lot of problems, like colors off and wrong letters. When I removed and cleaned the customs, I noticed a some legs were bent and some were broken.
Surprised it actually worked. Got a few "parts" boards from a friend which came with a lot of customs.

Any reason I can't test them in this board to see if they work? Other than the risk of breaking the current good ones when I remove and replace them.

 

[andrewb]

Shipping AR's is relatively pricey, so it's usually only cost effective to trade in multiples at a time, as any credit I give you for a single one ends up being cancelled by what it'll cost you to ship it in.

However I sell refurbed AR-II-01's for $48 each shipped, with 1-year warranty. You could also replace the 2N3055 on that bad one, and it would likely get you back up and running. However they can be difficult to desolder with just a hand pump. It really helps to have a gun for those, as the traces are very thick on the back, so you need to get a lot of heat into them, which can be hard with an iron and manual sucker.

As for Galaga, I don't repair those boards, but I do know that with a lot of customs, the packages are the problem, where the legs break easily. Combine that with bad sockets, and you could be in for a bad time if you just want to try swapping them, if the chips or sockets look corroded at all.

So it's going to depend on the condition the chips/boards are in. But if they're ok you should be able to swap parts around and see if you can get any improvement. However that can go south quickly if you start breaking legs, and getting broken legs stuck in sockets, etc. I have full capability to replace sockets and repair broken legs, etc. But if you don't, and you're new to board work, you can make a mess very quickly.

But don't let that discourage you if you want to learn. I just recommend having a good desoldering gun, iron, good quality solder, and watch a few youtube tutorials on soldering technique before attempting repairs you haven't tried before. There are also some good threads here about repairing broken legs on custom chips.

 

[gcpowers]

I just saw this thread after being PMed and wanted to chime in. The parts came from a trusted source and are not likely counterfeits. Additionally I burn them in for 24 hours before shipping.

 

[nulogix]

I just saw this thread after being PMed and wanted to chime in. The parts came from a trusted source and are not likely counterfeits. Additionally I burn them in for 24 hours before shipping.

Definitely a trusted source. Maybe just a bad one, then? I'll replace it and see what happens. No biggie. I just figured you'd want to know.

 

[nulogix]

I have the +5v dialed in at 4.97v on the dig dug board. Should I adjust it to get to 5.0v?

Also, is it a big deal that I'm getting 12.2v at the +10.3v test point on the dig dug board?

Also, should I refurb the original AR2's that I have? (I have 2 originals, one from a centipede and one from a millipede)

 

[andrewb]

The 10.3 normally runs between 12 and 14V. That's normal.

You want the voltage on the board to be no more than 5.0V. I run mine at 4.95. They'll work down to 4.8 or so, and any more than 5.0 and you're just burning up more power and wearing everything out faster.

As for refurbs, you don't need to recap AR's, as the original caps are always still good. (People here know I post about this weekly, but most people still go out and waste 20 bucks on cap kits for them).

The only part that normally wears is the 2N3055, which is what does the heavy lifting. If everything is already working, that's the only thing you need to replace, and you should be good for another 30 years. But you should always replace any original 3055's with date codes from the early 80's, as they're going to have a lot of hours on them. It's like driving around on bald tires, a they can take out your game board if they fail and internally short. But a new one will eliminate that problem for several more decades.

 

[nulogix]

Dig dug has been playing fine until tonight. (If you remember played fine, then AR went out and it was all better after different AR)

Tonight it was doing fine then all of a sudden started a low hum. When I coin up I can play but it's glitching and flickering a lot and will occasionally show the black and white squares test pattern on top of the game play, but the game keeps playing and does not reset. Turned it off and let it sit for a while. Turned it back on and same problem.

Am I right in assuming this different AR has likely gone out on this one, too? I turned it off and haven't started playing with it.

 

[andrewb]

Get out your DMM and check the AR voltages. Unplug the game board immediately, just in case there is an issue with the power system.

Measure the 10.3V DC in, 5V out (on the positive side of the C1 cap), as well as the AC value on the 10.3 test point (which should be less than 0.500V AC).

If the AC is high, your big blue is bad. That's what I'd suspect first. But if that's the case you can measure it to confirm.

 

[nulogix]

Will do that. That would suck as the big blue is brand new.

Thanks.

Get out your DMM and check the AR voltages. Unplug the game board immediately, just in case there is an issue with the power system.

Measure the 10.3V DC in, 5V out (on the positive side of the C1 cap), as well as the AC value on the 10.3 test point (which should be less than 0.500V AC).

If the AC is high, your big blue is bad. That's what I'd suspect first. But if that's the case you can measure it to confirm.

 

[andrewb]

The other possibilities are audio related. A bad LM324 on the game board, or possibly a bad TDA2002 on the AR. Either can fail and potentially short and mess up the power rail that is connected to them.

Easiest thing would be to swap another AR in there first (after checking the big blue). And always test the AR voltages before connecting the game board.

 

[nulogix]

Holy Eff. Voltage is > doubled in 5v.

 

[nulogix]

More testing..... is this pointing to big blue?