The operating pressure required to operate the switch was slightly lower with the factory fitted switches.They measured exactly the same physical dimensions, and had identical characteristics with two minor differences: So I compared the buttons in the trackball with the C&K ones from DigiKey. Anyway that wouldn’t explain why it was becoming impossible to drag with the trackball – it was like the button was letting go. As it turned out the debounce patterns were almost identical without too much noise at all. To check this I hooked up my oscilloscope to the buttons inside the device, and compared their debounce patterns to some high quality C&K switches from digi-key.
Originally I thought the cause of the problem was probably cheap microswitches with a horrible debounce pattern. There are many reports of this problem with these trackballs, the reviews on sites such as Amazon almost always mention it. Click the thumbnail above to see all the components laid out. When re-assembling be careful to align the on-off switch with the tiny slide switch on the bottom of the PCB, so that it is in the correct position for operating the switch once it’s all put back together. In the time honoured fashion: Reassembly is the reverse of the disassembly procedure. That’s all there is to it, a nice design, easy to disassemble and easy to reassemble. It will be lying in it’s position in the lower case just waiting to drop out onto the floor, never to be seen again. Once you lift out the PCB be careful not to lose the tiny plastic switch cover that forms the ON/OFF switch. The circuit board lifts out when you gently pull the battery contacts out from the guides. Look out for the one just below the two auxiliary switches it is easy to miss. It uses two sub-minature microswitches for the left and right buttons and two board mounted captive tactile switches for the auxiliary buttons.īy removing 4 more screws you can remove the entire circuit board complete. With the case separated we can see that this trackball uses a single board, and an optical image sensor for tracking the ball movements. It’s a shame it is let down by the small problem that it becomes unusable after just a few weeks! (Your mileage my vary, I use mine all day every day). Looking at the case you can see a lot of design and engineering has gone into producing this device. With all the screws removed the two case halves just pull apart, there are no catches or lugs. I guess this is Logitech’s attempt at detecting tampering with the device since you have to damage or remove the label to get to the 5th case screw. Gently feel for the screw hole under the lable using the tip of the screwdriver, you’ll find it right below the ‘5’ where it says “1.5V AA”. There is one more screw to find, and it hides under the battery compartment label. Now remove the 5 case screws, one from under each of the pads you removed, and one near the ball hole. You don’t need to remove the pad nearest the ball hole, there is no screw hiding under there. They can be easily lifted out and if you are careful you can put them back again later without any damage. Next remove three of the small rubber pads – they cover some of the case screws. To open the trackball first remove all the major external removable parts: The ball battery cover and micro-receiver if it is still hiding inside the battery compartment.
In this post we will teardown the M570 and repair the cause of the problem. I have had several of these over the years and they have all suffered from the same problem: after just a few weeks of using them, they start to develop problems like double-clicking and dropping files when you are trying to drag. For anyone, like me, who suffers from RSI in the wrist, it is an ideal replacement for a mouse as it removes all the moving back and forth – your wrist stays in one position and does not move when using it. The Logitech M570 is one of very few thumb-operated trackballs on the market.