Missile command woes

[andyman]

Last part of my restoration and at 3am this morning I gave up.

Board was repaired by IronGiant, he did say its not a reliable board so no problem, but now has no video output, have checked everything else and board is playing, so working ok apart from video. I have traced back as far as 82S25 (colour ram) @ L7, everything up to that point seems to be ok but its either this or the 157 feeding it, would anyone concur, as I do not have the parts to replace.

I am only at about 40% technical know how, so any pointers would be great, 1st ever Atari board I've worked on but I can already see it wont be the last, vector next

Andy.

 

[virtvic]

What? you haven't totally minted this one up in 3 days? Andy, you're slipping

You've seen 'Game Over', right?

 

[andyman]

Hey listen, ths one is a PITA, cab is done, monitor is in (and it works), coin door is done, board works, coin, credit, flashing start buttons, start, game plays. Its just I cant see it

Atari stuff is hard work, not easy like Midway & Williams cabs

Andy.

[edit : yeah, have Gameover, enjoyed that]
andyman2011-07-24 17:49:55

 

[virtvic]

It does seem that Atari cabs are the flakiest, but they're also the nicest looking and certainly the best games.

I actually got my Battlezone working yesterday by replacing the connectors and prodding one of the chips on the maths board. Just got to remake some of the little handle plungers for the joystick.

 

[Adrian Purser]

74LS157 are awful. They account for a large percentage of the problems I've found on the boards I have fixed most recently. My logic comparator seems to have the 157 in there permanently. I don't know if this is the problem but I tend to always check 157 first.

 

[guddler]

Without digging out the schems and checking out what's what I wouldn't know on specifics, however I'd concur with Ade that 157's can be a source of problems. Especially if worked hard.

I wouldn't agree about Atari boards though. Give me an Atari board over a Williams board any day of the week.

 

[andyman]

Cant be bothered now but will check the 157 out tomorrow, don't have any so ordered a few, cheers guys

Andy.

 

[andyman]

Right, whilst waiting for my parts to arrive and out of sheer 'I have the chip so why not try' I replaced the 175 @ L8 as this is where all video lines end up, now I have a pure white screen which jumps when I press the reset button on the board so I have a signal at least and its good from there to the monitor, just full on.

Andy.

 

[VectorGlow]

Does the game still play blind?

If so, it's a case of now tracing back from that 175 to see where the video outputs are suddenly stopping, ie on which chip. Could well be the 157 @ L5, but a good possibility is also the 82S25 RAM @ L7. If not, keep workings backwards.

Damn Missile Commands, so prone to new faults cropping up .........

 

[Alpha1]

Does the game still play blind?

If so, it's a case of now tracing back from that 175 to see where the video outputs are suddenly stopping, ie on which chip. Could well be the 157 @ L5, but a good possibility is also the 82S25 RAM @ L7. If not, keep workings backwards.

Damn Missile Commands, so prone to new faults cropping up .........

Someone clever should make a replacement board that plugs into the original loom, hint hint.

 

[DanP]

While they're at it they should do a Asteroids, a Pole Position, and a Multi Colour vector

 

[Alpha1]

While they're at it they should do a Asteroids, a Pole Position, and a Multi Colour vector

Yeah Phil.

 

[andyman]

It does still play blind Phil, yeah. Just got the ram in the post so will replace & see what happens. Also agree with above, save you some stress in the future

Back in a bit

Andy.

 

[Equites]

Hurry up and fix it will ye, so slow.....

 

[andyman]

We have Missile Command

Components replaced 74LS175, N3101AN (82S25 replacement)

Off to play, bye

 

[VectorGlow]

There ya go - easy.

 

[andyman]

So why the f*** do you keep moaning about them Phil

Maybe an AR rebuild is needed too, scratchy sounds for 5 mins, might also be the dodgy pot

Andy.

 

[andyman]

Andy.

 

[Alpha1]

Not a bad lineup duder, looks ace in the dark.

 

[andyman]

There are another 8 cabs in there (Only 2 non working), need to tidy up big style and do a widescreen shot ala

Quite an old one now so needs updating

Andy.