Breaking it off the board is also a bad idea. There are some crude ways of de-soldering it with a regular soldering iron (which you can find on Youtube) but you can damage nearby traces or accidentally remove something else along with the cap, so you have to be very-very careful. In order to remove this cap you'll need a hot air rework station. If you have it - it'll help you to locate the voltage sensing ciruit (our target capacitor is connected to it on one end, and to ground on the other). Also, you may want to flip the board and find a test pad marked 'ADC'. A nearby cap should be on the same circuit. The other two pins of both are connected together and the trace will go to one of the pins of that SONIX microcontroller. The second one ( '124') should go to the ground. One of those resistors must be directly connected to the battery's '+' terminal (probably the one marked '104'). In order to confirm it you'll need a multimeter w/ continuity test function and some steady hands. I am not 100% sure, but it looks quite close. If you are not familiar with basic electronics, then it's probably better to find someone more experienced. It's hard to tell for sure without poking and prodding around w/ multimeter. Thank you for your attention, and if you want more stuff like this, or more complex repair logs - let me know. Now I finally have something more intimidating than a semi-working-sparkly-white-mini-wireless-mouse-for-kids to use in my workshop. After removing it, I tested the mouse and. My measurements confirmed that both resistors are OK, so the only remaining suspect was that bypass cap. I say 'wasted', because afterwards I found an ADC testpoint on the flipside of the PCB, made specifically for dumbassess like me.ДЄlso, notice my contraption for holding a probe on a ground pin I was using my other hand to hold the phone.Д«asically, it uses a voltage divider to sense the current from the battery and keep this signal under 2.8V:ДЄs you can see, R30 and R31 form a voltage divider, and for some reason engineers at A4Tech added a bypass capacitor, which is totally pointless cause there should be no significant voltage spikes or jitter on this line (there are already too many caps near the battery and charging circuit to take care of this problem).ДЇrom the high-school physics class you should know that our at 4.1V should give approximately 2.6V on the sense pin, so something is pulling that value lower than it should be (only 2.2V is there), which can be a bad resistor, bad cap, bad soldering etc. My first suspect was a faulty battery, but my multimeter said otherwise: it was almost fully charged and did not show any signs of malfunctioning.ДЄfter a wasted minute of poking and prodding random stuff with my multimeter I finally found the sensing part. Brief initial inspection showed that everything on the PCB is powered from a built-in 2.8V step-down converter, which made my life easier in finding the sensing circuit (should be the only part besides charging IC that is connected directly to the battery). It has the same old NRF24L01 controller for wireless communication (used in anything from cheap $2 laptop mice to high-end Logitech G-series wireless mice), also has an entry-level AVAGO A3050 optical sensor and a SONIX USB HID controller. It's a fairly standard layout for a 'slightly-above-average' wireless mouse. This is what it does when connected to PC: It worked fine when hooked up to the charger, but once disconnected - the indicator drops to 0%, the mouse starts to blink fast (indicating low charge), and shuts down within a minute. Today on my surgical desk I found a brand new Bloody RT7 wireless gaming mouse with an unusual factory defect: it did not properly sense the charge of the internal battery and always reported it as empty. Maybe this info will be useful or at least interesting to someone, so don't throw any rotten tomatoes, and just enjoy some boring reading materials. I'm too lazy to do extensive youtube videos, so we'll go with some mundane stuff like pictures, diagrams and text I figured I'd start sharing some random repair logs from my workshop, cause I have no other hobbies, and someone might find this useful (maybe not today, but decades from now).

A4tech bloody r8