CH Products RollerMouse poor tracking

[Ozric]

I have a vintage CH Products DT225 (branded Rollermouse) trackball that I recently tried to start using, only to find that it the ball is having a hard time moving the rollers inside. Right-left works pretty well, but up and down require quite a lot of pressure on the ball to work and it is not consistent. I have opened it up but there does not seem to be much in the way of adjustment to be done.
Has anyone had a similar problem or know of a solution? Could it be that it is just worn out by the previous owner? I can not see any wear in the inside of it or on the ball.

[Archie]

To start with, DT225 and RollerMouse are two totally different (but visually similar) trackballs. Which one you're actually referring to?

[Ozric]

To start with, DT225 and RollerMouse are two totally different (but visually similar) trackballs. Which one you're actually referring to?

Okay, I was just assuming they are the same thing since to me they look the same and are made by the same company.
Comparing these:
DT225
RollerMouse
Also RollerMouse

I have the one that's the same model as the box above, but a PS/2 version for PCs.

[Archie]

The reason I'm asking is, they use completely different mechanics. The symptoms you're describing, if referred to the Trackball Pro (aka DT225), mean ball bearings have dried out and/or contaminated grease, and needs replacement or disassembling & re-lubrication. In case of RollerMouse, there's no any ball bearings, just primitive plastic bushings - so if they're worn, it's very unlikely you can restore normal operation, but attempt to clean and lubricate them is worth trying anyway, though.

There's also chance that some LEDs are degraded, or the mask came out of alignment - but it's difficult to check without an oscilloscope or logic analyzer.

[Ozric]

The reason I'm asking is, they use completely different mechanics. The symptoms you're describing, if referred to the Trackball Pro (aka DT225), mean ball bearings have dried out and/or contaminated grease, and needs replacement or disassembling & re-lubrication. In case of RollerMouse, there's no any ball bearings, just primitive plastic bushings - so if they're worn, it's very unlikely you can restore normal operation, but attempt to clean and lubricate them is worth trying anyway, though.

There's also chance that some LEDs are degraded, or the mask came out of alignment - but it's difficult to check without an oscilloscope or logic analyzer.

Okay, thanks for the info, I just assumed they were the same thing.
I did open it up, and what is happening is that the ball is not making good enough contact against the metal rods to spin them. That is why it works better with more pressure, because the ball is making heavier contact against the rods.
If I spin the rods by hand the cursor moves 100% fine, so the sensor part seems good.

When you say plastic bushings, does that mean that the ball is not supposed to rest directly against the metal rods, and that I am missing some parts inside the thing?

[Archie]

That's interesting! On DT225 the ball indeed drive steel shafts directly, while on RollerMouse there's a kind of plastic rollers surrounding them. Is there any possibility that your device is a Frankenstein made by previous owner by mixing DT225 and RM parts?

Posting a picture(s) of internals will greatly simplify further discussion I think...

[Ozric]

That's interesting! On DT225 the ball indeed drive steel shafts directly, while on RollerMouse there's a kind of plastic rollers surrounding them. Is there any possibility that your device is a Frankenstein made by previous owner by mixing DT225 and RM parts?

Posting a picture(s) of internals will greatly simplify further discussion I think...

Interesting, I will take and post pictures tomorrow when I am back at the office where the RollerMouse currently is.

[Archie]

Ok. If possible, make several pics from different angles with the ball removed, as well as top cover flipped over, please!

[GuilleAcoustic]

@Ozric: If that can help, here's a picture of my Trackball PRO ball suspension. I changed the rods once since the ball carved a deep groove into them after a few years of heavy use.

[Ozric]

Here are the pictures of my RollerMouse:

https://imgur.com/a/poFqzVR

[GuilleAcoustic]

Here are the pictures of my RollerMouse:

https://imgur.com/a/poFqzVR

Now that's weird ... I was expecting something like this ...



Maybe you have one of the latest Rollermouse, just before they released the Trackball PRO / DT225.

When you're spinning the rod by hand, do you feel any mechanical resistance ? Can it spin freely with a nice initial impulse or does it stop quickly ?

[Archie]

GuilleAcoustic, glad to see you back! I'd like to say big thanks for your article about DT225 conversion! Actually, I've used parts of your Arduino code to do similar thing, but with full 4-button support.

[Archie]

Here are the pictures of my RollerMouse:

https://imgur.com/a/poFqzVR

Unbelievable, but this is absolutely standard DT225. Mechanics & switches are the same, and PCB does not have ROLLERMOUSE silk text. I'm pretty sure someone relabeled it (thousands of these trackballs were shipped fith OEM labels, and maybe the owner wanted to transplant "genuine" CH nameplate, or the like?

[Archie]

For stuck bearings, you can either replace them (but avoid cheap Chinese crap), or restore. This is how I did that with my DT225:
https://forum.trackballs.eu/viewtopic.php?f=18&t=12

[Ozric]

When you're spinning the rod by hand, do you feel any mechanical resistance ? Can it spin freely with a nice initial impulse or does it stop quickly ?

Flicking the plastic wheel at the end, I can get them to rotate maybe one revolution on their own at most. I am guessing they should be a bit more free than that?

Can you just pop out the rods with their bearings and wheel? I have not dared pull at them yet.

Unbelievable, but this is absolutely standard DT225. Mechanics & switches are the same, and PCB does not have ROLLERMOUSE silk text. I'm pretty sure someone relabeled it (thousands of these trackballs were shipped fith OEM labels, and maybe the owner wanted to transplant "genuine" CH nameplate, or the like?

So it's a very rare special specimen worth thousands?

I don't know the timeline for RollerMouse/DT225, but this one is from early 1991, datecode on the chip on the PCB is 9105.

[Archie]

Flicking the plastic wheel at the end, I can get them to rotate maybe one revolution on their own at most. I am guessing they should be a bit more free than that?

Yes, it should spin for several seconds if you flick the chaft by finger.

Can you just pop out the rods with their bearings and wheel? I have not dared pull at them yet.

Just pull them up, yes. And BTW don't touch 4 screws near the discs: they're for LED mask alignment.

So it's a very rare special specimen worth thousands?

Maybe.

I don't know the timeline for RollerMouse/DT225, but this one is from early 1991, datecode on the chip on the PCB is 9105.

They coexisted initially. At least I have old RM advertizings dated 89 - 91. Then RM was discontinued, and only high-quality Trackball Pro (renamed DT225 as CH Products dropped consumer market) survived.

[GuilleAcoustic]

GuilleAcoustic, glad to see you back! I'd like to say big thanks for your article about DT225 conversion! Actually, I've used parts of your Arduino code to do similar thing, but with full 4-button support.

Thanks for the welcome back . I've been deskless for the last 3 years, but I'm back on track (building my small geek place).

I'm glad that my article and code are of any use. If you have any link to what you've donne, I'd be very interested. I'm still planning a drop in replacement board for the DT225/Trackball Pro.

[Archie]

Well, article about Trackball Pro as such is currently in progress, and I can't say when it will be ready to publish (serious lack of free time for my hobbies), but the same code was used for modding Curtis trackball - there's a link to my .INO file somewhere inside:
https://forum.trackballs.eu/viewtopic.php?f=16&t=18

Teardown of trackball itself is here:
https://forum.trackballs.eu/viewtopic.php?f=17&t=15

BTW, have you found any good quadrature algorithm with acceleration support?

[Ozric]

I managed to get the shafts out and remove the bearings, but instead of trying to clean them I went ahead and ordered some new ones in what I think is the correct size (4x9x4mm). We'll see if they work otherwise I will look into opening and cleaning the original ones.

[Archie]

in what I think is the correct size (4x9x4mm).

Millimeters aren't suitable units here. DT225 uses Imperial-standard R2 bearings (1/8" x 3/8" x 5/32" dimensions).

[GuilleAcoustic]

Millimeters aren't suitable units here.

Why ? Metric system is used worldwide, while imperial units are barely used outside of USA / UK (with a mix of both systems in Canada).

I was looking for optical encoders today and a 2mm shaft is equivalent to 0.079" ... Millimeters are so much more easy (4mm = 5/32" oh dear...)

[Archie]

Why ?

Because they're different, perhaps?

You're free to call R2 bearings 3.175 x 9.525 x 3.967mm ones, of course, or try to mount PC hard disk with M4 screws.

[GuilleAcoustic]

Why ?

Because they're different, perhaps?

You're free to call R2 bearings 3.175 x 9.525 x 3.967mm ones, of course, or try to mount PC hard disk with M4 screws.

Here R2's are sold as 3.18x9.53x3.97mm bearings . Lets call them R2 lol.

I thought you meant that metric was forbidden on this forum.

[Archie]

I thought you meant that metric was forbidden on this forum.

That's would be really funny!

[Ozric]

in what I think is the correct size (4x9x4mm).

Millimeters aren't suitable units here. DT225 uses Imperial-standard R2 bearings (1/8" x 3/8" x 5/32" dimensions).

Oh dear. Well, the seller I bought from has that exact size as well so I will just order a set of those instead. Thanks for the info!

[Ozric]

I have now received the correct bearing and put them into the trackball and it works!
Thank you for the help in sorting this out.

[Archie]

Great! Glad you've successfully repaired it.

[GuilleAcoustic]

great news !!

[ifohancroft]

Sorry to hijack this thread but I am absolutely in-love with this trackball since seeing pictures of its construction and I'm curious:

1. If I am understanding correctly, the ball is supposed to touch and rotate the bearings, not the rods themselves, right?
2. What are the two black plastic wheels on the outside of the bearings of the two rods?
3. What are the LED masks and what they are for?

P.S. A bad joke/pun I heard somewhere, that I may be misremembering: What's a bear doing in a forest? It's bearing.

[GuilleAcoustic]

Sorry to hijack this thread but I am absolutely in-love with this trackball since seeing pictures of its construction and I'm curious:

1. If I am understanding correctly, the ball is supposed to touch and rotate the bearings, not the rods themselves, right?
2. What are the two black plastic wheels on the outside of the bearings of the two rods?
3. What are the LED masks and what they are for?

P.S. A bad joke/pun I heard somewhere, that I may be misremembering: What's a bear doing in a forest? It's bearing.

The ball is supposed to touch the rods in order for the black plastic wheels to rotate.

Those wheels are encoding wheel and they work in pair with LEDs / Sensors to generate what's called "quadrature signals".



You can read my conversion thread about this trackball if you want: viewtopic.php?f=3&t=9874