Author Topic: Logitech Marble Mouse T-BC21 - replacing switches  (Read 18741 times)

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Offline ebg9000

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Logitech Marble Mouse T-BC21 - replacing switches
« on: Tue, 30 May 2023, 10:37:11 »
I'm interested in replacing the Button4 switch in my T-BC21.

I've been using a Logitech Marble Mouse T-BC21 for many years, along with SteerMouse to program Button4 to engage scrolling with the ball. My preferred method of scrolling is to hold Button4 and scroll with the ball, then release to disengage scrolling. (I vastly prefer this to clicking Button4 once which locks scrolling, and then clicking again to unlock).

However, over time all my trackballs start to lose consistency in keeping the button engaged. If I am off-center slightly, or not applying maximum pressure to the center of Button4, the scroll function will disengage. This will happen without an audible "click" of the button. This happens on both the newer models (logi) and the older models (logitech logo).

I would consider changing to a different trackball, but I am quite happy with this method of scrolling. But obviously this issue makes it frustrating to the point of unusable.

Has anyone replaced the switches in the Marble Mouse? Are there better switches I could use for Button4?

« Last Edit: Tue, 30 May 2023, 12:47:02 by ebg9000 »

Offline jagiapa9

  • Posts: 1
Re: Logitech Marble Mouse T-BC21 - replacing switches
« Reply #1 on: Wed, 03 December 2025, 02:30:56 »
The most similar ones I can think of would be the Gameball or Kensington Orbit.

Other finger balls that you might want to consider could be Elecom's Huge or Deft Pro, Kensington's Expert and the L-Trac.

Offline Findecanor

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Re: Logitech Marble Mouse T-BC21 - replacing switches
« Reply #2 on: Wed, 03 December 2025, 06:24:00 »
I haven't done that, but I've replaced switches in my mice a couple times.
From what I have seen, these trackballs have the same type of 3-pin microswitches as most mice. There is a lot of info in the Definitive Omron Switch Guide for Mice thread.

To replace them, you'd need a soldering iron, solder sucker and solder wick, and of course new solder.
If you are unfamiliar with soldering, there are quite a few "mouse switch replacement" guides on Youtube.

However, I suspect that there could also be wear on the plastic parts that press onto the microswitches, so I would recommend looking for that.
If there is, then do post a picture! Perhaps there is something that could be repaired/reinforced with application of epoxy putty and/or gluing on an additional piece of plastic, but it depends on how the part is supposed to work.

--
ps. "jagiapa9" above is not a real human, but a spambot account that reposted a post it had scraped off Reddit.
It has been reported.
« Last Edit: Wed, 03 December 2025, 06:26:34 by Findecanor »
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