Help with Missile Command repair

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

Hello Group,

I am trying to fix a Missile Command, which wouldn't boot (would just
run the coin counter), and in test mode would give me the 5th high
beep. According to the Manual, that is RAM K4.

Yesterday I replaced the RAM chip (my gosh... I had no idea it would be
THAT difficult! Took me all afternoon) and the problem was solved.
Game booted, and ran for about 5 or 10 minutes while I adjusted the
monitor (up to this point, I didn't even know if the monitor worked at
all - so I was happy).

Then it locked up with a white screen. I ran Test mode again and now I
am getting the 8th RAM error.

Now before I try replacing another RAM, which I know will take me
hours... is it likely, or possible, that my botched K4 RAM job is
causing this 8th RAM error? Or, is it possible something else is
causing these RAM's to fail (such as a power supply problem?)
Everything on the P/S tested fine, 5V was a hair low but I adjusted it
up slightly with the pot.

Any help is appreciated. I will try just replacing the 8th RAM if
nothing else, but I thought someone might have more insight into this
problem.

Thanks in advance,
Wade
wadelanham at hotmail dot com
 
Archived from groups: rec.games.video.arcade.collecting (More info?)

Those old RAM chips are probably failing one at a time. As you noticed if
you don't have the proper tools you can ruin a good board. If you're
replacing RAM chips I hope you're installing sockets. If you solder in a
RAM chip without socket you just cut the life of that chip in ½ due to heat
stress.



As for the PS, it maybe a good idea to replace the old filter caps but as
long as your voltage is adjusted correctly it's usually not a problem.



If you don't want to deal with the repairs yourself I work on these boards
for $65 plus parts.


Andre
www.arcadesolution.com



<wadelanham@hotmail.com> wrote in message
news:1112106229.607154.164650@o13g2000cwo.googlegroups.com...
> Hello Group,
>
> I am trying to fix a Missile Command, which wouldn't boot (would just
> run the coin counter), and in test mode would give me the 5th high
> beep. According to the Manual, that is RAM K4.
>
> Yesterday I replaced the RAM chip (my gosh... I had no idea it would be
> THAT difficult! Took me all afternoon) and the problem was solved.
> Game booted, and ran for about 5 or 10 minutes while I adjusted the
> monitor (up to this point, I didn't even know if the monitor worked at
> all - so I was happy).
>
> Then it locked up with a white screen. I ran Test mode again and now I
> am getting the 8th RAM error.
>
> Now before I try replacing another RAM, which I know will take me
> hours... is it likely, or possible, that my botched K4 RAM job is
> causing this 8th RAM error? Or, is it possible something else is
> causing these RAM's to fail (such as a power supply problem?)
> Everything on the P/S tested fine, 5V was a hair low but I adjusted it
> up slightly with the pot.
>
> Any help is appreciated. I will try just replacing the 8th RAM if
> nothing else, but I thought someone might have more insight into this
> problem.
>
> Thanks in advance,
> Wade
> wadelanham at hotmail dot com
>
 
Archived from groups: rec.games.video.arcade.collecting (More info?)

No, I didn't install sockets. I bought sockets and plenty of chips to
do just that, but I couldn't solder in the sockets. It was too small
of an area to work. I bought the smallest iron tip I could find, and
filed it even sharper. Still hard to work on something that small. So
I decided to try the RAM chip directly.

I found one of the legs wasn't soldered well enough. I fixed that, and
the game works again. So either the Test Mode reporting RAM 8 was a
mistake (it was really just the RAM 4 problem), or maybe that RAM 8
chip is intermittent. I haven't run the game long enough since then to
know yet (just about 15 minutes).

If I end up with another RAM error, I will try to install a socket
instead, maybe I'll have better luck. If not, then maybe I'll send it
off for a proper repair before I really screw things up. :)

I'll post a follow up later after the game has been used more, whether
this RAM repair holds up or not.

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

> No, I didn't install sockets. I bought sockets and plenty of chips to
> do just that, but I couldn't solder in the sockets. It was too small
> of an area to work. I bought the smallest iron tip I could find, and
> filed it even sharper. Still hard to work on something that small. So
> I decided to try the RAM chip directly.

This makes absolutely no sense... you must be doing something very wrong....

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

hey he is probably using the smallest tip for a 1450 weller solder gun
thats available!



--
Mickster

Visit my website and see my arcade!!

http://mickster.freeservers.com

"Matt Osborn" <osborn@alum.mit.edu> wrote in message
news:1112212074.214202@hqnntp01.autodesk.com...
>> No, I didn't install sockets. I bought sockets and plenty of chips to
>> do just that, but I couldn't solder in the sockets. It was too small
>> of an area to work. I bought the smallest iron tip I could find, and
>> filed it even sharper. Still hard to work on something that small. So
>> I decided to try the RAM chip directly.
>
> This makes absolutely no sense... you must be doing something very
> wrong....
>
> Matt
>
>
>
 
Archived from groups: rec.games.video.arcade.collecting (More info?)

You guys are harsh!!

Forgive me for not being an expert and trying to repair a board myself!
:) Cut me some slack...

I admit, I had a tough time of it, but I am happy because it is
working, and I'm crossing my fingers that it continues to work. Tips
on how to replace chips like this are appreciated.

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

The Mickster was just being funny....

My comment was not criticism, but genuine concern.
You said that soldering a chip directly in was easier than
soldering a socket, and that you were sharpening your tip.
For someone who knows about board repair, these are
both red flags... clear indications that your technique is wrong.

I was hoping you would elaborate on your approach,
and then the folks here could give you some pointers.
After a bit of ridicule, of course! Just kidding. ;-)

Matt

<wadelanham@hotmail.com> wrote in message
news:1112298649.524294.15470@l41g2000cwc.googlegroups.com...
> You guys are harsh!!
>
> Forgive me for not being an expert and trying to repair a board myself!
> :) Cut me some slack...
>
> I admit, I had a tough time of it, but I am happy because it is
> working, and I'm crossing my fingers that it continues to work. Tips
> on how to replace chips like this are appreciated.
>
> Wade
>
 
Archived from groups: rec.games.video.arcade.collecting (More info?)

I wouldn't say a normal dip package is small. Hate to see what he thinks of
surface mount stuff .
"Mickey Johnson" <mickster@derbyworks.net> wrote in message
news:114mbijkcpc9q62@news.supernews.com...
> hey he is probably using the smallest tip for a 1450 weller solder gun
> thats available!
>
>
>
> --
> Mickster
>
> Visit my website and see my arcade!!
>
> http://mickster.freeservers.com
>
> "Matt Osborn" <osborn@alum.mit.edu> wrote in message
> news:1112212074.214202@hqnntp01.autodesk.com...
> >> No, I didn't install sockets. I bought sockets and plenty of chips to
> >> do just that, but I couldn't solder in the sockets. It was too small
> >> of an area to work. I bought the smallest iron tip I could find, and
> >> filed it even sharper. Still hard to work on something that small. So
> >> I decided to try the RAM chip directly.
> >
> > This makes absolutely no sense... you must be doing something very
> > wrong....
> >
> > Matt
> >
> >
> >
>
>
 
Archived from groups: rec.games.video.arcade.collecting (More info?)

Matt Osborn wrote:
> The Mickster was just being funny....
>
> My comment was not criticism, but genuine concern.
> You said that soldering a chip directly in was easier than
> soldering a socket, and that you were sharpening your tip.
> For someone who knows about board repair, these are
> both red flags... clear indications that your technique is wrong.
>
> I was hoping you would elaborate on your approach,
> and then the folks here could give you some pointers.
> After a bit of ridicule, of course! Just kidding. ;-)
>
> Matt

Matt,

Okay, I can handle the ridicule... :)

This is probably what made the problem so difficult for me: I had
trouble removing the original chip, and thus damaged the thin traces
right at the chip. It might normally be possible to just solder from
the bottom, but I was afraid the connections wouldn't be made at the
top of the board (most of the traces were on the top, not the bottom).
And after first soldering in the chip, I had that exact problem.
Several of the pins I had to reflow the solder to get a connection to
each chip above and below the one I was replacing.

I originally planned to socket and replace *ALL* 8 of the RAM chips.
But as long as it took me to do this one, I definitely won't be doing
that. "If it ain't broke, don't fix it." If RAM goes bad in the
future, I will try again to socket them. Maybe I'll be successful with
some tricks, or something else (maybe there is a better solder for this
application than what I'm using?)

I'm using a cheap 25W (I think) iron. The tip was about like a
blunt pencil lead, but I filed it to be like a reasonably sharp pencil.
The solder is thinner rosin core, but not the smallest Radio Shack
has. I think it might have been .032? I would have to check to be
sure.

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

First thing,

1) Always just cut the chip out (with nippers or a razor blade). You are not
trying to save the chip, but the save the traces and the pcb.

2) You can use a cheap 25 watt iron, but you need to be more carefull and it
won't be as easy as a better iron

3) Practice has a lot to do with it, actually you would be better off
starting out with cap kits on monitors than logic pcbs

4) Unless you are ripping the pins out without using enough heat, the
through holes should almost always be good, what this means is, when the job
is done right, you only solder to the solder side, not the component side.

5) Make sure you have plenty of light and time to do the job

6) Accept the fact, that most likely at your skill level you are not doing
the job right and if you want it done right, don't attempt it. Send it to
someone that knows what they are doing. Think about it, would you want to
pay for the quality of job you are doing? So keep that in mind if you plan
on selling any of these games later.

7) Plan on ruining some of the stuff you are attempting to fix in the
beginning.

--
Mickster

Visit my website and see my arcade!!

http://mickster.freeservers.com

<wadelanham@hotmail.com> wrote in message
news:1112362718.914712.319620@o13g2000cwo.googlegroups.com...
> Matt Osborn wrote:
>> The Mickster was just being funny....
>>
>> My comment was not criticism, but genuine concern.
>> You said that soldering a chip directly in was easier than
>> soldering a socket, and that you were sharpening your tip.
>> For someone who knows about board repair, these are
>> both red flags... clear indications that your technique is wrong.
>>
>> I was hoping you would elaborate on your approach,
>> and then the folks here could give you some pointers.
>> After a bit of ridicule, of course! Just kidding. ;-)
>>
>> Matt
>
> Matt,
>
> Okay, I can handle the ridicule... :)
>
> This is probably what made the problem so difficult for me: I had
> trouble removing the original chip, and thus damaged the thin traces
> right at the chip. It might normally be possible to just solder from
> the bottom, but I was afraid the connections wouldn't be made at the
> top of the board (most of the traces were on the top, not the bottom).
> And after first soldering in the chip, I had that exact problem.
> Several of the pins I had to reflow the solder to get a connection to
> each chip above and below the one I was replacing.
>
> I originally planned to socket and replace *ALL* 8 of the RAM chips.
> But as long as it took me to do this one, I definitely won't be doing
> that. "If it ain't broke, don't fix it." If RAM goes bad in the
> future, I will try again to socket them. Maybe I'll be successful with
> some tricks, or something else (maybe there is a better solder for this
> application than what I'm using?)
>
> I'm using a cheap 25W (I think) iron. The tip was about like a
> blunt pencil lead, but I filed it to be like a reasonably sharp pencil.
> The solder is thinner rosin core, but not the smallest Radio Shack
> has. I think it might have been .032? I would have to check to be
> sure.
>
> Thanks,
> Wade
>
 
Archived from groups: rec.games.video.arcade.collecting (More info?)

> This is probably what made the problem so difficult for me: I had
> trouble removing the original chip, and thus damaged the thin traces
> right at the chip. It might normally be possible to just solder from
> the bottom, but I was afraid the connections wouldn't be made at the
> top of the board (most of the traces were on the top, not the bottom).
> And after first soldering in the chip, I had that exact problem.
> Several of the pins I had to reflow the solder to get a connection to
> each chip above and below the one I was replacing.

VaxX posted some good tips for you.
Clipping the chip out and plucking the legs one-by-one is the way
to go, especially on a board like MC. If the desoldering process is
clean then you won't have to worry about the trace connections on
the top of the board. As long as the via (plated through-hole) isn't
damaged, then the connection will be good.

If you did damage a via or lift a top trace you can often repair such
damage by installing machine-pin strip sockets (as they will allow
some top access). And that will require a fine-tip iron and a very
steady hand. But that's really not a job that a beginner should
attempt to tackle.

Matt
 
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