Help with Missile Command repair

Archived from groups: rec.games.video.arcade.collecting (More info?)

wadelan...@hotmail.com wrote:
> Okay, after moving my game and re-assembling it, it is not working.
 
> I could really use some help troubleshooting it.
>
> Test mode doesn't seem to report anything wrong. I get static, then
a
> low and a high beep. From the manual, this looks like the self test
> thinks everything is okay.
>
> The Player 1 and Player 2 start buttons light up a bit dim. If I hit
> launch buttons, or roll the trackball, the screen will kind of
flicker,
> and sometimes I will get a screen full of garbage. Usually, it is a
> sprite or a character of some sort just repeated across the entire
> screen.
>
> Since the test mode reports okay, all I know to check is the DC
> voltages. I checked 5 and 12 on the board, and they were okay. I'm
> not sure what to try next (I will check ALL the voltages, probably
> tonight).
>
> Any help is appreciated!
>
> Thanks,
> Wade

Wade, reseat the edge connector. Secondly...... make sure all the fuses
are o.k.

John

Archived from groups: rec.games.video.arcade.collecting (More info?)

Baraka wrote:
> Wade, reseat the edge connector. Secondly...... make sure all the
fuses
> are o.k.
>
> John

I tried reseating the connector a couple of times. It didn't give me
any problems the few times I had the board out previously, so I think
the chances are a bit low that is the problem. I will test for
continuity from the board to the harness, on each of the lines.

I will also go over all the fuses.

Any other suggestions?

Wade

Archived from groups: rec.games.video.arcade.collecting (More info?)

wadelanham@hotmail.com wrote:
Okay, after moving my game and re-assembling it, it is not working.  
I could really use some help troubleshooting it.

Test mode doesn't seem to report anything wrong. I get static, then a
low and a high beep. From the manual, this looks like the self test
thinks everything is okay.

The Player 1 and Player 2 start buttons light up a bit dim. If I hit
launch buttons, or roll the trackball, the screen will kind of flicker,
and sometimes I will get a screen full of garbage. Usually, it is a
sprite or a character of some sort just repeated across the entire
screen.

Since the test mode reports okay, all I know to check is the DC
voltages. I checked 5 and 12 on the board, and they were okay. I'm
not sure what to try next (I will check ALL the voltages, probably
tonight).

Any help is appreciated!

Thanks,
Wade


I've repaired probably 50 MC boards, but I don't recall seeing
the symptoms you're describing. All I can suggest are the
obvious things...

Clean the edge connector
Reseat all of the socketed IC's
Reseat all harness connectors

If you've measured the DC voltages on the main board (not the
A/D II board), then you don't have an edge connector problem.

Good Luck,

John Hermann
Buy, Sell, Trade, and Repair Video and Pinball Machines.
Located near Dallas, TX.
http://www.geocities.com/SiliconValley/Circuit/8393

Archived from groups: rec.games.video.arcade.collecting (More info?)

John,

Thanks for the tips. That makes sense, if I'm getting good voltages
to the board then I don't need to worry about the edge connector (as
far as getting it to boot up). Should I adjust the 5V to exactly 5.0
or should I make it slightly higher? I will reseat all the socketed
chips, hadn't tried that one yet.

Thanks!
Wade

Archived from groups: rec.games.video.arcade.collecting (More info?)

Okay, I adjusted the 5V to 5.1V, and verified the 12V and 10V were
correct.

I also removed and reseated all the socketed chips, but there was no
change.

What would be a good next step? Should I get a new set of eeproms?

Wade

wadelanham@hotmail.com wrote:
> John,
>
> Thanks for the tips. That makes sense, if I'm getting good
voltages
> to the board then I don't need to worry about the edge connector (as
> far as getting it to boot up). Should I adjust the 5V to exactly 5.0
> or should I make it slightly higher? I will reseat all the socketed
> chips, hadn't tried that one yet.
>
> Thanks!
> Wade

Archived from groups: rec.games.video.arcade.collecting (More info?)

> What would be a good next step? Should I get a new set of eeproms?

You might consider sending it out for repair. That way you
aren't paying to solve problems that might not exist. There
are several shops that can do that sort of work, including ours.

Some places (like ours) have a "testing-only" fee, which prevents
you having to pay full price if the board is really OK (meaning
that the problem is actually something in your cab).

Alex
----
ayeckley@elektronforge.com
www.elektronforge.com

Archived from groups: rec.games.video.arcade.collecting (More info?)

Alex,

I am aware of repair options, and I will take them if necessary.
However, I would really like to perform the repair myself, if possible,
even if it doesn't save much money. At any given time, at least one of
my games is broken, so I feel it is a requirement that I learn to
repair some of these games. I would like to exhaust all possible
"do-it-yourself" repair options before sending the board out.

Thanks,
Wade

Archived from groups: rec.games.video.arcade.collecting (More info?)

I just wanted to post a follow up for this thread. Last night, I
removed all the chips and sanded them with some fine sandpaper. They
didn't appear very dirty at all, but I didn't know what else to try
short of sending it out for repair. Well, it worked!!

Thanks for the help and suggestions. It's great to finally have
this game working!

Wade

Archived from groups: rec.games.video.arcade.collecting (More info?)

>I just wanted to post a follow up for this thread. Last night, I
>removed all the chips and sanded them with some fine sandpaper. They
>didn't appear very dirty at all, but I didn't know what else to try
>short of sending it out for repair. Well, it worked!!

You'll probably want to buy a replacement set of ROMs then.
By sanding the legs (even using something as fine as 400 grit), you've
removed the plating from the underlying steel. Over time
(days/weeks/months) they'll rust now from moisture in the atmosphere
and cause new problems. The rust is going to be worse than the original
problem. Sorry for the gloomy prognosis.

We recommend that folks use something like 3M Scotchbrite (tm)
to clean ICs legs and edge connectors since it removes only
microscopic amounts of plating. A stainless steel brush works
well also (we've never seen any evidence that any embedded
stainless particles have caused galvanic corrosion).

Alex
----
ayeckley@elektronforge.com
www.elektronforge.com