problem with marble madness and other system 1 games

[Superully]

problem with marble madness and other system 1 games

hi guys!
i have a problem with all my system 1 games. no matter which game i insert, they all show problems after about 10 seconds after i turn on the machine.

- marble madness: the demo stars running, but when the timer reaches 54 (sometimes 53), the demo suddenly pauses, the screen starts to flicker, everything is distorted except the marble and the fonts (see attached picture)
- roadblasters: the demo starts running, after a couple of seconds the screen somehow splits into two horizontal halves (see attached picture), i can't add credits / start the game
- indiana jones: the demo start running, after a couple of seconds the sounds suddenly goes bad - like "scratches" on an old record

i have tested all the boards (system 1 mainboard, all the gameboards, the ariii board) on a friends machine (where everything's working) and i have also replaced both the ariii board and the system 1 mainboard with replacement versions in my cab - no effect! furthermore, i have replaced the switching power supply with a new one and i have also experimented with its voltage output (giving it more or less power) - still the same errors.

judging from what i've done so far, it either has to be a problem with the wiring or something on the power supply assembly. or am i missing something here?

thx a lot for all your comments, hopefully we can figure this out together!

 

[DustyBri]

If your board sets and A/R III work in your friend's cabinet, I would think you are right to assume that your problems may be caused by the wiring or power supply.

Since you have the A/R III, I believe you should have the isolation transform set with the "big blue" capacitor. I have read posts were people have reported similar issues in other Atari games that are often resolved by replacing this capacitor. The AC line filter or rectifier could also be bad. It is very unlikely but you may also want to test the isolation transformer voltages to make sure it does not have an internal short.

The wiring might also be an issue because I believe that most System 1 cabinets with A/R IIIs did not originally have a switching power supply. (That is what the A/R III board, rectifier, and "big blue" capacitor do so there was really no need.) I drew a diagram of how I think a switching power supply should be hooked up based on others descriptions in another post but since I have a newer System 1 cabinet (Audio II board version) I can not confirm if it is correct. (see http://forums.arcade-museum.com/showthread.php?t=55661 for details)

It might also be possible that the problem could result from a poor or dirty connection somewhere.

 

[Superully]

@dusty: thx a lot for your answer, but before we "dive in deeper", let's take one step back. when i got my system 1 cab first, it was hosuing roadblasters, which was working perfectly back then. however, i wanted to run marble madness in the cab, so i got myself a mm daughterboard and plugged that in. here's what happened then:

http://forums.arcade-museum.com/showthread.php?t=88573&highlight=marble+madness

continuation: i went to a friend of mine with the mm daughterboard, he plugged it into his machine, it worked perfectly. so we switched our system 1 mainboards (because he doesn't have mm anyways) and i thought i was good to go. once back home, i plugged in the new system 1 mainboard and the mm daughterboard - and the above mentioned error occured. what's strange is the fact that neither indiana jones nor roadblasters are working now - which they did before. but let me repeat again: all three games are working in my friend's cab - the only thing we didn't test in his cab are the wiring and the power supply board.

to make a long story short: what would you check next? how should i check the wiring? what could be dirty?

as for the power supply board: mine doesn't have the big blue, please find attached pictures of the power supply board and the ariii board.

i'm thankful for every further comment!

 

[DustyBri]

You actually have the "Audio II" board like my RoadBlasters, not the A/R III.

The photo below is of cartouche's Audio/Regulator III in case you want to know what it looks like.

The A/R III is the one found on the older Atari System 1 games and requires the "Big Blue." Since you do not have that version, you can disregard most of what I said in my last post.

It is unlikely that the AC filter or isolation transformer would have failed between the last time it worked and the time you had swapped main boards with your friend. None of the connections in your photos look like they have burns and should be clean enough to make good contact. I guess when I had suggested to check all that, I did not realize that your game worked at one time.

There were two different versions of the motherboards. The LSI version is the newer one that was used with the Audio II board and the TTL version is the one that was used with the older Audio/Regulator III board. The P101 pin out is not the same but I am not sure if Atari actually used a different size connection to prevent hooking up the wrong board to the other's wiring harness. If your old motherboard worked fine in the cabinet where your current motherboard came from, you can probably rule that out as an issue.

Another possibility is that you could have reversed a connection somewhere. You might check the Ground and +5V wires on the power supply. I do not know what the European version used since the schematic packages available online are for the US version with red and brown wires. Also check P101 and all of the other connections and make sure they are tight. If you have a voltmeter, you can check the continuity of the wiring to make sure you did not accidently break a wire when you swapped out the boards.

There is another wire or two in your photo that is not connected (in front of the transformer). I do not remember anything being unhooked on mine. It could be for voltage selection so it might not be important.