Centipede Trackball Issues

Torin

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I have a Centipede that has a trackball that isn't quite right. When I push it up, it will sometimes go up but then it goes right back down again. I have to spin it pretty well for it to go up but then, while it is spinning, it will go back down on its own. Left and right movements are fine.

Things I have done:

Put in new rollers and bearings
tried two different sets of optic boards (same result for both)
Swapped out the metal wheels

Dave (ArcRevival) told me to check the edge connector and I wiggled it but didn't see any differences. That is the extent of testing the edge connector up to this point, as I need to get the lock open on the back.

Just wanted to see if anyone had any ideas or have seen this issue before.

Thanks,

Torin
 
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I would replace the edge connector ( stop being lazy ! ) But there is also an Atari service bulletin that talks about changing the input resistors at location R83 to R86 and R130 to R133 to 3.3k ohm instead of 10 ohm. Some motherboards have those changed from the factory. Check and see what version your trackball pcb is. I think the -02's have to have the 3.3 ohm resistors on the main pcb
 
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I would replace the edge connector ( stop being lazy ! ) But there is also an Atari service bulletin that talks about changing the input resistors at location R83 to R86 and R130 to R133 to 3.3k ohm instead of 10 ohm. Some motherboards have those changed from the factory. Check and see what version your trackball pcb is. I think the -02's have to have the 3.3 ohm resistors on the main pcb


I know, I know. I am a lazy ass when it comes to replacing edge connectors for sure. I actually came across that service bulletin looking for info on this issue. Once I get the back door off, I'll check out the trackball pcb on the motherboard.
 
Turns out this is a board issue. Tried a known working trackball with the same result. Tried another known working board and the trackball works perfectly in the same cabinet.

Looks like its time to change out those resistors Dave mentioned. This is rev-01 and it looks like it has the old resistors and caps. I think I will change out some of the caps in that area as well. I will post the results.
 
i just had this same issue. i bought the board on ebay as 100% working and it had the same problem you had. I sent it back to the seller and he fixed it. It was a broken trace on the board that controlls the up and down.
 
i just had this same issue. i bought the board on ebay as 100% working and it had the same problem you had. I sent it back to the seller and he fixed it. It was a broken trace on the board that controlls the up and down.

WTF, you have one of those stupid hats on your avatar. You are out of my will and off my Christmas card list.
 
Turns out this is a board issue. Tried a known working trackball with the same result. Tried another known working board and the trackball works perfectly in the same cabinet.

Looks like its time to change out those resistors Dave mentioned. This is rev-01 and it looks like it has the old resistors and caps. I think I will change out some of the caps in that area as well. I will post the results.

It "could" be that one board is working better with the edge connector than the other.
Just saying....
 
Check the voltage at the trackball. If the +5v is low, it will give irratic results.

If it's low, it's could be the edge connector. ;)

I checked the voltages on both optic boards and they are both between 4.95 and 4.99, so I think we are good there. I still think its the pcb. There is one replaced chip that was pretty much a hack job. I think it is the chip at A10. It needs to be socketed because the solder job is not pretty. I guess it could also be the resistors that Dave mentioned from the Atari bulletin release found here:

http://arcarc.xmission.com/PDF_Misc/Atari Tech Bulletin (Mini trackballs).pdf

Thanks for all the help. If this PCB is shoddy, I just might have to purchase a Millipede pcb and get the Braze kit to have both. I don't really have the resources to do much PCB work.
 
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