Resurrection of Missile Command

hindered

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So, I have a Missile command that was completely dead when I inherited it -- dead monitor, no signs of life from the game boards. The internal wiring of this cab is a bit confusing. There's 2 ISO transformers, one standalone, and one part of the power brick on the bottom of the cab (next to the big blue cap). There's a place where the white/black AC wires are cut and held together with quick disconnects for no apparent reason. Not sure why this has been done.

Here's a list of progress I've made so far:

GO7 was completely dead. Rebuild kit from Bob Roberts brought it back to life. Can't get the picture to quite snap into sync, slow roll horizontally no matter what I do. That's for a different thread though, and I haven't checked Fromm's flowchart yet so that might tell me what to do anyway. Monitor has nice sharp bright color, though, which is a great start.

AR/II had a blown R29 and R30. I replaced them and performed the sense mod so I could do some further testing without damaging anything (in theory). Here's the test values I got: (test point value : actual reading)

36VAC: 13.6
-22VDC: -18
22VDC: 17.3
12VDC: 11.9
-5VDC: -12.7
10.3VDC: 10.3

I took out the main PCB and gave it a visual inspection. There's minor burning on the fingerboard so I know I'll need to replace the edge connector at some point. I tested all the roms and one of them was bad, so I burned a new one and replaced it. Reseated the processor just for fun. I took the board back to the cabinet and hooked it all up, powered it on. Tested at the 5vdc test point.

5VDC: 5

The light on the PCB lit up, one of the coin counters starts clicking like crazy. I hear some explosion sounds through the speaker and other random game sounds but it doesn't sound like it's working properly, no big shock given the voltages from the AR/II. Putting it in test mode doesn't seem to make any difference. I can't tell if anything was on screen because the monitor's still on the test bench due to the sync issue.

Where do I start from here? I'm assuming an AR/II rebuild is the first stop, but the fact that -36VAC (which I think is the voltage coming into the board) is off by so much makes me think that something might be wrong with the power in the cab even before it reaches the AR/II.

Anyone got any guidance?
 
36 is actualy tested at 2 places,so if you test one place and it gives you 13-18 the other place might give you the remaining amount that makes up 36 as its split.

yes get the ar2 recapped,change the big blue.

after that i dont know as i aint into boards,my knowledge does not go past power,i know little about monitors and boards.

but,yes i got a mc cocktail,i actualy have 2,1 is a worker now the other isnt,am waiting for a donor cab to arrive to get another worker (hopefully) from them.
:)
 
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I always get confused testing for the 36AC on the AR board. I suspect though that the 36AC is good, as the AR rectifies the 36AC and produces +12VDC, and -5VDC. Off the 36AC the AR also throws out the +\-22, but you can forget about these as they're neither used nor needed by Missile Command.

I reckon your power all looks good. Don't be thrown by the -5VDC giving such a high reading, as it will do this when unloaded.

In short, your problems don't appear to be power related.
 
There are two test lugs on the AR-II labeled 36VAC. Put your meter in AC mode and the leads on each of the two test lugs.

The main culprit on the cpu board are those rotten sockets Atari used. Just about every board I get I replace all 8 (or 9) of those and also the bypass capacitors if they used anything other than ceramic.

You can also carefully check the board for shorted leads on the solder side, and bypass capacitors inadvertently shorting on the component side.
 
There are two test lugs on the AR-II labeled 36VAC. Put your meter in AC mode and the leads on each of the two test lugs.

The main culprit on the cpu board are those rotten sockets Atari used. Just about every board I get I replace all 8 (or 9) of those and also the bypass capacitors if they used anything other than ceramic.

You can also carefully check the board for shorted leads on the solder side, and bypass capacitors inadvertently shorting on the component side.

Ok, NOT looking forward to replacing all those sockets. If it comes to it, I'll do it. I powered up the game blind again last night and was getting no sounds, although the coin counters were still firing like crazy. I went ahead and disconnected them. Not sure why there was no exploding sounds or anything. Didn't matter what position the test switch was in. Wonder why things would change from last night to tonight, maybe something fried that ROM that was originally bad.. guess I'll know more when I can get the monitor back in there. Hopefully my parts order from Jameco comes in tomorrow, then I can hook up the monitor again. Wish I had known to order some sockets, though. Everything I have on hand is for the slimmer chips like 2114/4116 etc. Nothing for eproms I don't think, and Radio Shack doesn't carry that width either..
 
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There's a fully working board on eBay right now. I'm sure if you contacted him directly he would give you the KLOV discount. :)

Ok, NOT looking forward to replacing all those sockets. If it comes to it, I'll do it. I powered up the game blind again last night and was getting no sounds, although the coin counters were still firing like crazy. I went ahead and disconnected them. Not sure why there was no exploding sounds or anything. Didn't matter what position the test switch was in. Wonder why things would change from last night to tonight, maybe something fried that ROM that was originally bad.. guess I'll know more when I can get the monitor back in there. Hopefully my parts order from Jameco comes in tomorrow, then I can hook up the monitor again. Wish I had known to order some sockets, though. Everything I have on hand is for the slimmer chips like 2114/4116 etc. Nothing for eproms I don't think, and Radio Shack doesn't carry that width either..
 
There's a fully working board on eBay right now. I'm sure if you contacted him directly he would give you the KLOV discount. :)

Yeah, I'm pretty cheap though. :) Maybe if it was the KLOV discount + "accepting the partially working board in trade" discount.
 
Ok, I got the monitor back into the cabinet today to check it out. Board is booting to a garbage rug pattern, purplish. I didn't think to take a picture but will get one later. The slam switch doesn't do anything, and it measures 1vdc when I meter it. I disconnected both counters. Strange thing, looks like there are a bunch of disconnected QDs in between the two coin mechs (see picture). Also, there are four molex connectors that could connect to the coin counters, but only two plugs to connect them to (the coin counters, see picture).

Coin lights don't work, I assume the bulbs are burned out but they meter at 0vdc, so I'm not getting 12vdc to the coin door -- didn't think to check if I'm getting 12vdc at the game board.

Also, around the area of the volume control, there are two wires not connected to anything with .187 QDs on the end. No clue what it's to.

Finally, it's last on my list to care about, but the marquee light won't turn on. It keeps flickering and the ends of the bulb glow, which means it needs a new starter typically. However, I replaced the starter, same deal. Bad ballast? If so, I'm probably just going to chuck it all for an under-cabinet fluorescent -- it's in pretty bad shape, bulb held in place with tape etc.

EDIT: Also, the 2nd isolation transformer I mentioned before appears to be standard, just like in the manual. Not sure why they did it that way, but hey. I'll leave well enough alone on that.
 

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The coin door voltage on MC uprights is, I think, 6.5VAC - which comes straight out of the transformer (rather than the AR2). Check the transformer for the 6.5 (can't remember which pins, but it'll be which ever ones the 2 blue wires in the molex connect to).

If 6.5VAC is present then check the fuse - which is in a really odd place - you'll find it on the floor of the cab, left hand side, close to the rear door.
 
The coin door wiring is set up to support three coin mechs (i.e. lockout coil and lamp).

Check the three voltages on the main board +5V, +12V, -5V. The latter two you can check on one of the DRAMs. IIRC only the the +5V has a dedicated test lug.
 
The coin door wiring is set up to support three coin mechs (i.e. lockout coil and lamp).

Check the three voltages on the main board +5V, +12V, -5V. The latter two you can check on one of the DRAMs. IIRC only the the +5V has a dedicated test lug.

Can you please be a bit more specific about how to test -5V and +12V? i.e. a chip location + which pins to check?
 
Can you please be a bit more specific about how to test -5V and +12V? i.e. a chip location + which pins to check?

Nevermind -- found +12v and -5v test points on the PCB. +12 is ~11.8 and -5 is -13.21.

EDIT: I also cleaned up some of the wiring today -- got rid of the quick disconnects/spades in the AC wiring in favor of molex connectors. Did the same for a twisted together speaker connection. Took a closer look at the edge connector, there are three loose wires, one white, one black, one red. One looks to be the ground to the control panel, and looks like it has accidentally ripped out of the pin. The black and white ones look to be cut deliberately, and one seems to be part of the sense circuit. I don't think this matters because I did the sense mod on the AR/II, right?
 
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The coin door voltage on MC uprights is, I think, 6.5VAC - which comes straight out of the transformer (rather than the AR2). Check the transformer for the 6.5 (can't remember which pins, but it'll be which ever ones the 2 blue wires in the molex connect to).

If 6.5VAC is present then check the fuse - which is in a really odd place - you'll find it on the floor of the cab, left hand side, close to the rear door.

JFYI page 20 of the MC manual shows 6.3vac coming from the AR/II. I haven't investigated this further yet.
 
It comes from the brick. All of the voltages from the AR are recitified.

Thanks for verifying. Guess the manual is wrong or I'm misinterpreting it.

What do you think about the -5v running so high under load? Guess I do need an AR/II rebuild? Might as well replace the big blue too?

Do you know what part from Bob Roberts I need to replace the edge connector?
 
JFYI page 20 of the MC manual shows 6.3vac coming from the AR/II. I haven't investigated this further yet.
Confusing isn't it? But as Bit_Slicer has confirmed the manual has got it wrong (although the Drawing Package has it right).

To add further confusion, on page 31 the manual sets out the power assembly diagram and parts list. The powers assembly parts list mentions fuse F6. You won't find that on the power assembly - that's because it's the one found on the cab floor I referred to earlier.

They don't make it easy, do they?
 
Thanks for verifying. Guess the manual is wrong or I'm misinterpreting it.

What do you think about the -5v running so high under load? Guess I do need an AR/II rebuild? Might as well replace the big blue too?

Do you know what part from Bob Roberts I need to replace the edge connector?

This weekend I have on my to-do list putting together some AR rebuild kits. These kits would cost the same as BR's, or less *gasp!*, and contain more of the critical parts needed to do the rebuild. I also have all the connector housings and split-crimps for standard Atari edge connectors.

I swear I need about 3-4 me's to get done all the things I want to accomplish! :p
 
And that is why it is cheaper in the long run to buy Bob's kits! You can always get more money... but the amount of time you have is pretty well set in stone...
 
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