I got a Missile Command today; it worked for 2 minutes

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I got a Missile Command today; it worked for 2 minutes

Before turning it on for the first time, I looked inside to make sure everything was connected. Everything looked okay so I turned it on. The attract mode came up and it looked perfect. I was about to put a quarter into it when the graphics got garbled and the screen started to roll. I turned it off and turned it back on, and it was now just a rolling white screen with a black rectangle of garbled graphics in the upper right hand corner of the screen.

The board has something from Braze which I don't know anything about, but I guess it is to allow it to play Super Missile Attack. I don't know if that thing is causing the problem or not. I reseated it (and reseated its own individual chips), along with the only other two chips on the board that were socketed, and I cleaned the card edge on the board as well as the card edge connector in the machine's wiring harness. Nothing changed.
 

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My Braze kit is oriented like yours is. My board doesn't have any of those big round orange capacitors like yours does though, nor does it look like it ever did. It also doesn't have any chips in the sockets shown at the bottom of your picture, like yours does. I guess that is because the Braze kit bypasses those. I assume those are for the original ROMs. I wish I had the original ROMs to test.

Also, this board has 3 card edges, but only one of them is used (the large J20 one which mates with the card edge connector in the machine's wiring harness). The smaller J19 edge looks like it has had a connector on it in the past, but there is nothing in the machine to connect to it now. The third card edge is quite small; the one down by the Braze kit. It doesn't look like it's ever been used for anything. What are they for?
 
My Braze kit is oriented like yours is. My board doesn't have any of those big round orange capacitors like yours does though, nor does it look like it ever did. It also doesn't have any chips in the sockets shown at the bottom of your picture, like yours does. I guess that is because the Braze kit bypasses those. I assume those are for the original ROMs. I wish I had the original ROMs to test.

Also, this board has 3 card edges, but only one of them is used (the large J20 one which mates with the card edge connector in the machine's wiring harness). The smaller J19 edge looks like it has had a connector on it in the past, but there is nothing in the machine to connect to it now. The third card edge is quite small; the one down by the Braze kit. It doesn't look like it's ever been used for anything. What are they for?

If it's an upright, only the largest connector (J20) should be used. If it's a cocktail, the connector next to J20 (J19, I think). The third connector is for some kind of system test rig. If your board was ever in a cocktail, it would show signs of use on that second connector.
 
My Braze kit is oriented like yours is. My board doesn't have any of those big round orange capacitors like yours does though, nor does it look like it ever did. It also doesn't have any chips in the sockets shown at the bottom of your picture, like yours does. I guess that is because the Braze kit bypasses those. I assume those are for the original ROMs. I wish I had the original ROMs to test.

Also, this board has 3 card edges, but only one of them is used (the large J20 one which mates with the card edge connector in the machine's wiring harness). The smaller J19 edge looks like it has had a connector on it in the past, but there is nothing in the machine to connect to it now. The third card edge is quite small; the one down by the Braze kit. It doesn't look like it's ever been used for anything. What are they for?

Also, my board doesn't have the big orange caps either - it has large greenish ones instead. As long as something is in those holes, you should be fine on that score.
 
Before turning it on for the first time, I looked inside to make sure everything was connected. Everything looked okay so I turned it on. The attract mode came up and it looked perfect. I was about to put a quarter into it when the graphics got garbled and the screen started to roll. I turned it off and turned it back on, and it was now just a rolling white screen with a black rectangle of garbled graphics in the upper right hand corner of the screen.

Have you had a go at checking the fuses? You might want to pop them out and meter them to make sure they are all OK.

If that doesn't work out, I'd check all the voltage test points on the main board and see if things are up to spec or not.
 
If it's an upright, only the largest connector (J20) should be used. If it's a cocktail, the connector next to J20 (J19, I think). The third connector is for some kind of system test rig. If your board was ever in a cocktail, it would show signs of use on that second connector.

Okay, that explains it then.

Also, my board doesn't have the big orange caps either - it has large greenish ones instead. As long as something is in those holes, you should be fine on that score.

Mine doesn't have any capacitors in that area at all. I looked at the Missile Command PCB on KLOV and it doesn't have those capacitors either - http://www.klov.com/images/11/1127075993.jpg. The ones without capacitors must be a different board revision or something.

Have you had a go at checking the fuses? You might want to pop them out and meter them to make sure they are all OK.

If that doesn't work out, I'd check all the voltage test points on the main board and see if things are up to spec or not.

Haven't done any of that yet. I wonder if the fact that the picture is rolling means anything to anyone. What causes a picture to roll? Doesn't that indicate lack of sync? I don't think the monitor is the problem though because the machine won't play blind. In test mode it does the same rolling screen, except it is green rather than white, and there is static coming from the speakers rather than silence.
 
I tested +5, -5, and +12 on the PCB's test points, and they were all fine.

My meter showed continuity on all the fuses.

There were test points on the PCB marked V-sync and H-sync. Those showed .12 VDC and .56 VDC respectively. I don't know what voltages they are supposed to show.
 
Now it is doing something different, since I checked all the fuses and metered some of the test points. Here is a short video showing what's on the screen.
 
Did you check the fuses holders themselves?Sometimes they fatigue over time and don't always make a solid connection.

I checked the open fuse holder. I don't know how I would check the fuse holders that are the fully contained twist on plastic cap type. Does the problem in the video I linked to look like something that could be caused by a bad fuse? I figured a bad fuse would just result in completely dead machine.
 
:eek: Holy crap Brian, you might want to remove the old ROMS! I know that on the Braze site it says that removing the old ROMs is 'optional', but unless the SMA kit has moved the program memory to a different address offset (which is doubtful!), then the old ROMs are electrically competing with the PROM on the kit. The result is a shortened life for your kit and/or ROMs!


Make sure the Braze kit itself is seated and properly oriented. And make sure the 6502 chip is in the right position on the kit as well. The kit should bypass any socketed chips.

Picture-1.jpg


here's a link to the braze troubleshoot site
http://www.brasington.org/arcade/mcm/ try that... good luck:)
 
If it's an upright, only the largest connector (J20) should be used. If it's a cocktail, the connector next to J20 (J19, I think).

That's true. The J19 connector is used for the player 2 trackball and buttons.

The third connector is for some kind of system test rig. If your board was ever in a cocktail, it would show signs of use on that second connector.

The small-pitched connector near the 6502 processor is used by the Atari CAT Box which was a piece of field test equipment operators used to troubleshoot. you don't need to worry about it.
 
Also, my board doesn't have the big orange caps either - it has large greenish ones instead. As long as something is in those holes, you should be fine on that score.

Those are the bypass capacitors for the DRAMs. You can find all different kinds of caps that were used, mylar, ceramic, etc. I think Atari just used whatever they had on hand or was cheapest at the time. Check the leads of the capacitors - sometimes they get mashed down and short-circuit other traces on the board.
 
Mine doesn't have any capacitors in that area at all.

Are you sure? That would shorten the life of your DRAMs, and could explain why it's failed.

Haven't done any of that yet. I wonder if the fact that the picture is rolling means anything to anyone. What causes a picture to roll? Doesn't that indicate lack of sync? I don't think the monitor is the problem though because the machine won't play blind.

What you're seeing is the processor flipping the screen up and down. It does this when the processor is trying to run code, but is getting constantly watchdogged.

In test mode it does the same rolling screen, except it is green rather than white, and there is static coming from the speakers rather than silence.

If you're getting alternating growl tones, that's self-test indicating a DRAM failure. I'm very certain you have one or more bad DRAMs.
 
Did you try the self test mode? Switch inside the coin door. Don't know if it works with braze kit installed. I would hope so. Usually ram is bad on these boards from the ones I've owned.
 
Are you sure? That would shorten the life of your DRAMs, and could explain why it's failed.

I guess mine does have capacitors there, but they have colored bands and look like resistors. Here is a picture showing C37 (sorry for the low quality webcam picture):

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What you're seeing is the processor flipping the screen up and down. It does this when the processor is trying to run code, but is getting constantly watchdogged.

If you're getting alternating growl tones, that's self-test indicating a DRAM failure. I'm very certain you have one or more bad DRAMs.

Did you happen to watch the video of the problem that I linked to? If not, here is the link. That shows what it is currently doing, which is different than what it was doing when I started this thread.

How many DRAMs are there on this board? (Edit: 8?) Where are they located on the board? (Edit: F4 through P4?) And are they available to buy new? If so, where; and what name or number should I look for? (Edit: 4116?)
 

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Those are ceramic capacitors. Sorry I can't watch the video from work, but I will try it when I get home.

How many DRAMs are there on this board? (Edit: 8?) Where are they located on the board? (Edit: F4 through P4?)

Correct, and correct.

And are they available to buy new? If so, where; and what name or number should I look for? (Edit: 4116?)

Yes, you can get them at www.coinopchips.com. I do work on these boards if you find you need help.
 
Those are ceramic capacitors. Sorry I can't watch the video from work, but I will try it when I get home.



Correct, and correct.



Yes, you can get them at www.coinopchips.com. I do work on these boards if you find you need help.

Thanks for the help and the offer to work on the board. I will first try the shotgun approach by replacing all 8 of the 4116 DRAMs (and adding sockets). That aspect of board repair is my specialty. I worked for two years in a PCB factory, inspecting and soldering boards with a Metcal iron (I now own my own Metcal).

Diagnosing a problem is something else entirely, and I know very little about that. At the PCB factory we had a Hewlett Packard HP 3070...

3857084840_7999135aa5_o.jpg


...with custom modules for each of the different types of boards we built and it would do a thorough diagnostic test on every single circuit and component on the board, and give a printout of any problems it found. It would be nice to have one of those at home with custom modules for all of the popular arcade boards. Too bad the machine costs about a quarter of a million dollars, and each custom module cost God-only-knows how much.

So anyway, if replacing all of the DRAMs doesn't fix it, I may send the board your way.

So just to verify, I need some of these, right? And are these the type of sockets that they would need? Do you know if those sockets in that link are double-wipe?
 
So just to verify, I need some of these, right? And are these the type of sockets that they would need? Do you know if those sockets in that link are double-wipe?

Yes, and I have no idea. I'm not sure what kind of sockets he sells. You might want to ask first. Good luck! :)
 
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