720 joystick rebuild issues

88mph

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I just disassembled, cleaned and lubed my 720 joystick. I removed the old plastic pivot ball, and replaced it with a newly manufactured one from RAM controls. I lubed everything up as indicated in the Atari manual, but I'm not getting the type of response I want on this controller. It's WAY better than it was, but it will only do about 360 degrees on its own momentum if I turn the stick really fast and then let go.

I think the culprit may be that the area immediately around the pivot ball (in the upper plastic housing) is worn out. The ball I removed didn't even look like the ball I replaced it with, it was so badly worn. I have some spare Gauntlet controllers here, I'm considering swapping in an upper housing to see if that makes things better.. Has anyone tried this? How much up and down play is a 720 joystick supposed to have? I can pull mine "up" about half a centimeter or so--that can't be good, can it?
 
A brand new pivot ball shouldn't cause much more friction. You don't want to over load anything with grease- too much grease can bog things down.

I would fiddle with different tensions on the little bicycle chain- sometimes looser is not better.
 
Thanks mrpeepers. Can you comment on how much up/down slop is acceptable in this stick? I'm thinking that the area surrounding my pivot ball may be enlarged to the point that the upper housing may need to be replaced. From what I can see, the chain doesn't seem to be the cause of the binding, but I will see if fiddling with the sprocket gets me better performance..
 
Dave from RAM controls would know exactly how much a brand new stick pulls up and down.

I my stick has about 1/8" of pull up slop in it. I think it is mainly from wear on the lower housing. The lower housing wears MUCH more than the upper.

How did things feel when before you attached the rest of the controller to the bottom of the stick?
 
The original Atari spec on this allowed up to 3/32" (0.09375") slop which I believe to be too much play. Atari was actually very loose with tolerances with nearly everything they made which has made my job of reproducing their parts with very tight tolerances that much more difficult.

Anyhow, if you have play beyond 3/32" on that pivot ball and the housing, it's simply too much and will negatively impact the performance of the controller.

I've seen play of 5/16" on completely tweaked controllers, so I guess 3/32" isn't too bad when you compare the two.

BTW, I should have the reproduction upper and lower housings done sometime soon. Once they're done, the 720 controller project will come to a quick finish.

Dave
 
I just measured, and it looks like I have about 1/8 inch of up/down slop on the controller. It didn't feel that great when it was just the stick in the upper/lower housing. It definitely makes sense that the lower housing would get more wear, now that I think about it. I think it's time to take this thing apart again..

Heh, this stick is well on its way to being 100% composed of RAM controls parts... :)
 
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Hey, what ever became of this project?

On a side note, does anyone know where I can snag a copy of a 720 users manual (pdf OK) that's newer than the 1st printing? I want one that shows the newer control stick and roller.

Also, I have those lower balls, bushings and rollers available now in case anyone wasn't aware of it. :)

Dave
 
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