Cherry MX2.0S RGB keyboard LED failure episode three

Following the previous two repair records of Cherry MX2.0S RGB LED failures (see earlier notes: Repair log of Cherry MX2.0S RGB keyboard lighting failure after more than 3 years , Cherry MX2.0S RGB keyboard LED failure repair log again), after about two months another group of keys (Ctrl, Shift, =, F11) developed the same fault:

Because I know this keyboard has the bad LED issue, I often subconsciously press keys repeatedly to trigger the lighting effect and check if any LEDs have died.

This time I caught it in the act, witnessing the entire process of this group of LEDs going from ‘normal to failing’:

At first, after triggering the normal lighting effect (I use a very bright effect as seen in the earlier video, with a constant effect it might be harder to notice a single color failure), the faulty group flashed red a few times then went dark. This state lasted a few days, then the red flashing time gradually increased after the effect ended. Finally it became the classic fault of red constantly on and unable to turn off. Most likely one LED’s red diode gradually aged and failed, with reverse leakage increasing until it permanently triggered red light.

Initially I thought since LEDs fail so often, I might as well ‘let it be’ and repair several at once later. But after some time no new failures appeared, so my OCD kicked in and I brought it home for ‘treatment’ again.

With the previous experience, this time it was straightforward. Using a multimeter I quickly located the faulty LED:

It was the F11 key. The red diode reverse reading was only about 0.76, compared to a normal one:

Around 2.2! I also checked all the other original LEDs (the replacement 5628 ball‑head reverse‑mount LEDs have different silkscreen markings on the common anode, so it is easy to tell which are new). I tested all the red diodes to try to find hidden problems. None were abnormal, readings were all around 2.2‑2.3 😂. So be it, I will just accept that other LEDs will age in the future.

Replaced with a new LED.

Cleaned with flux remover. Since this was a night repair, the LED and pad alignment was not perfect, but after powering on the RGB worked normally. Fault repaired again, episode three ends.