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Fixing up a CX-80 Trak Ball (angular button variant)


CZroe

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I've got a junky CX-80 that I'd like to fix up. It's missing a foot, it doesn't turn very well, the ball is scratched and dull, and the rollers just stop turning when you spin too fast (at least when the top is off). I'm guessing some cleaning and lubrication will help but I'm having trouble figuring out how to access them for that. I could free the PCB by desoldering the cables that connect to the encoders but that seems a little extreme. Still, I can't easily see or access whatever is holding them down with the main PCB permanently attached on top by short permanently-soldered cables. Even if it's just simple plastic snaps, I'd risk breaking them just to find out.

 

Looks like this but in much worse shape:

103b9255c0f932b303cebcb3af75dac0.jpg

 

Before I go much further, I hear about CX-80s with CX-22 internals that are styled after the 800XL, CX-80s that have been factory-modified to function as an Amiga mouse, and CX-80s that are only compatible with the Atari 8-bit PC line. The one with angular (not circular/round) buttons only seems to exist as a CX-80, but mine is all black (even the ball) and is definitely not styled after the 800XL. From what I've read, that means it does not have CX-22 internals.

 

Now, I never read that it had to have CX-22 internals to be fully compatible with the CX-22. When people say that some CX-80s are not compatible with the CX-22, do they just mean that it doesn't have a JS/TB switch (joystick/trak ball) or that it was modified as an Atari ST mouse? Mine does have the switch, so I assume it's 2600-compatible despite not having CX-22 internals or being designed to match the 800XL (all black; angular non-round buttons; insides don't match the CX-22 service manual).

 

I thought that perhaps the ones that aren't CX-22 compatible are one and the same with those that were modified for use as an Atari ST mouse. I looked for confirmation and I've found some pretty thorough attempts to clarify the differences where such a simple distinction should have been made, and wasn't. That's why I can only assume that there are three different CX-80s.

 

It has the JS/TB switch. I haven't tested it on my 800/800XL systems yet because I don't have a Trak Ball compatible game and I really don't see the appeal of using it in joystick mode. I did just get an Ultimate Atari Cart yesterday so I'm suddenly interested in fixing it up. I may get some 2600/7800 TB hacks some time in the future if I can fix this up and confirm what it is compatible with.

 

In case anyone is confused by the first few replies, I quickly replaced the OP with this message after a Tapatalk glitch:

Edit: More than half of the time I make a thread Tapatalk bombs and says to try again. I always copy my text, back out, and find that it made TWO threads even though I DIDN'T try again. Grrr...

When the second thread disappeared I restored the OP. Edited by CZroe
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If you're looking for help, we're going to need a bit more to go on. ;)

You have a whole other thread. ;) I deliberately removed it from this duplicate one as soon as Tapatalk created it. Would've removed the title too but Tapatalk doesn't let you. Edited by CZroe
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...aaaaand despite my fast-action someone has already deleted the other thread without looking to see which should stay. I guess a mod/admin was operating almost as fast!

 

Restored OP incoming...

 

Edit: Restored OP.

Edited by CZroe
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If it has the TB/JS switch then, from what I've read, it would have been functionally identical to the CX-22.

 

In TB mode, the CX22 supplies two output lines that represent direction: one for left/right and one for up/down. It also supplies two clock or motion outputs, one for left/right and the other for up/down. I generally refer to this as "Direction+Clock". I've seen it called "Up/Down Clock".

 

An alternate output from a trackball would be what is widely known as Quadrature encoded or Gray Code output. This is a bit less processed than the above mentioned scheme. It is the same signal that's output directly by the optical encoders that translate the motion of the ball into digital signals. So, generally speaking, this protocol already exists in the trackball circuitry, but can be processed through circuitry to provide the Direction+Clock style output.

 

In order to make a trackball work as an ST Mouse, the quadrature encoded motion signals would have been placed on the output instead of the "Direction+Clock" signals.

 

In large part, I think most would agree with you about using the trackball as a joystick. By their nature, digital joystick games can't respond proportionally to the controller input so much of the value of a trackball is lost in the translation.

 

If the only trackball I had was a CX80 or CX22 with the mode switch, and I owned an Atari ST computer, I'd be tempted to try modifying it so that the mode switch allowed choosing between the two true trackball protocols instead of trackball and joystick emulator. That would allow playing any trackball games that wanted the Dir+Clk signals and would allow using the trackball as an ST Mouse (although, I think the mouse had two buttons and the TB's seem to be wired with effectively one button.)

 

I've kicked around the idea of making my CX22 be a tri-mode, but really don't have a need since I've modifed my CX53 (5200 trackball) to make it act any way I want. If I had an ST, I'd build a mod to make the two buttons act independently to be more ST mouse-like.

 

I am curious how well a CX80 or CX22 would act as a mouse. I'd expect it to be relatively slow.

 

In case you aren't aware, there have been a number of 2600 games very well adapted recently to be played with a trackball. If you have a Harmony cartridge for the 2600, they're worth checking out. They will support your CX80 whether or not it has been modified to act like an ST mouse.

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Thanks for the input. If it shows signs of life at all I'll just go ahead and unsolder the cables to get at the roller bearings and lubricate.

 

Seeing in the service manual that there are two versions of the CX-22 (one is JS-mode only), I have to assume that there is no JS-only CX-80. and that this confusion comes from modified CX-80s that only work with earlier systems in JS-mode (since the Trak Ball mode is simulating an Atari ST mouse).

 

Your solution with the CX-53 sounds almost exactly like something I was thinking but don't have the knowledge to pull off. I was thinking of mounting a DB panel mount connector to the CX-53 itself but I don't have one and I do have this so... *shrug* I'd love to see a write-up!

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I didn't really write it up and share it as I produced and sold the enhancement as a product (briefly and very small quantity...almost broke even. :)).

 

I figured out a way to do it without any actual physical modifications to the CX53: completely reversible and doesn't interfere with use as a 5200 trackball.

http://atariage.com/forums/topic/247242-interest-check-5200-trak-ball-mod-to-play-2600-tb-games/

 

Just earlier today, I tested it with an 8 bit (XEGS) to assure that the console could supply sufficient power to the controller to run it. I believe that with a minor modification, I could support both ST mouse buttons. But, I don't really know if the second button is even used to any significant degree by ST software.

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I didn't really write it up and share it as I produced and sold the enhancement as a product (briefly and very small quantity...almost broke even. :)).

 

I figured out a way to do it without any actual physical modifications to the CX53: completely reversible and doesn't interfere with use as a 5200 trackball.

http://atariage.com/forums/topic/247242-interest-check-5200-trak-ball-mod-to-play-2600-tb-games/

 

Just earlier today, I tested it with an 8 bit (XEGS) to assure that the console could supply sufficient power to the controller to run it. I believe that with a minor modification, I could support both ST mouse buttons. But, I don't really know if the second button is even used to any significant degree by ST software.

Very cool. I don't have a CX-53 but I'd be interested in buying one to have this done if you ever start doing it again, especially because my CX-80 barely works. :(

 

I finally got the opportunity to test it with Asteroids on my original Atari 800 using the Ultimate Atari Cart and it barely works. :( It rolls fine but as soon as your hand leaves the ball it keeps rolling (as it should) while the cursor stops moving (as it shouldn't). Also, even when it is rolling it will often jumpy the wrong way. I tried to navigate the Ultimate Atari Cart's menus with it in JS mode but it will move down about two out of five times even when you're rolling up (seems worse when moving slower/more carefully).

 

Yeah, it definitely needs to be fixed up. Any tips for getting under the PCB without desoldering? It's as simple as freeing the encoders but I can't see them under the PCB to know which way to pry/lift without breaking them or the housing.

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I finally got the opportunity to test it with Asteroids on my original Atari 800 using the Ultimate Atari Cart and it barely works. :( It rolls fine but as soon as your hand leaves the ball it keeps rolling (as it should) while the cursor stops moving (as it shouldn't). Also, even when it is rolling it will often jumpy the wrong way. I tried to navigate the Ultimate Atari Cart's menus with it in JS mode but it will move down about two out of five times even when you're rolling up (seems worse when moving slower/more carefully).

 

Yeah, it definitely needs to be fixed up. Any tips for getting under the PCB without desoldering? It's as simple as freeing the encoders but I can't see them under the PCB to know which way to pry/lift without breaking them or the housing.

It does sound like it has a problem. Make sure the tiny slits in the optical encoders are dust free. Same with the encoder wheels. That's what I'd check first. The fact that it sometimes goes backward in joystick mode mimics the general behavior I'd expect when the encoders are spitting out invalid gray code state changes.

 

I don't know the CX80 circuitry, but it could also be a failure in whatever chip is squaring up/boosting the signals for the encoders. Probably a 339.

[EDIT]: it appears to use 40106 Shmitt triggers to clean up the signal according to the schematic that Alex79 drew up and posted here: http://atariage.com/forums/topic/243434-what-2600-titles-couldshould-have-trak-ball-support-added/page-5?do=findComment&comment=3377853

 

It could also be further downstream in the circuitry. I think a bad cap in the "one-shot" (CD4098 chip) RC network could cause it to hold the output signal for a very short time which would mean you have to keep spinning the ball fast to get it to output a signal long enough for the game to recognize it as a joystick input.

 

If you have a Harmony cartridge for the 2600 (and a 2600, naturally), there's a test program that visualizes the output signals and that might let you see a pattern to the failure.

 

An oscilloscope would make short work of the troubleshooting. :)

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  • 2 weeks later...

I did finally get in.

 

 

It appears that the encoder boards slide straight up and aren't really clipped in at all (friction fit). I removed the rollers and oiled the bearings. It runs MUCH smoother though it's still hard to navigate menus precisely (slowing down for precision causes it to register the wrong direction). It seems to work flawlessly in Trak-Ball mode with Missile Command.

 

I took measurements of the bearing inner and outer diameters while I was in:

https://imgur.com/a/qo2An

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