keys: R replay · Space pause · H record mode · arrows step · URL: ?rec&dur=15&paused&loop
Two things go wrong, and they stack.
Schematic cross-section · HE108: LED at the bottom of the switch, clear cap, legend printed on top · Razer BlackWidow Elite alongside as the control
Where the light starts
bottom
south-facing LED, front of the switch
Where the legend sits
top
printed on the top face, opaque
What reaches your eye
a glow
in the dark, backlight on
HE108 · clear cap, printed legendthe cap glows, the letter stays dark
Razer · opaque cap, translucent legenddark key, glowing letter
FAULT 1 · THE LIGHT POOLS AT THE BOTTOM OF A SEE-THROUGH CAPFAULT 2 · THE LEGEND IS INK ON THE SURFACE. IT BLOCKS WHAT DOES ARRIVECAPS THAT LIGHT PROPERLY HAVE TO BE OPAQUE. THE FIX COSTS YOU THE CLEAR CAPS
Fault 1: the LED sits at the bottom of the switch, so the light enters a transparent cap low and pools there; little reaches the top face. Fault 2: the legend is opaque ink printed on that top face, so what does arrive is blocked rather than passed. Fixing either alone gets you nowhere while the other stands, which is why Razer caps on the arrow keys did not help.
The Razer’s LED sits at the top of the switch under the legend, its cap is opaque and works as a light guide, and the legend is the only exit · shown in the dark-room footage, same camera, locked exposure · schematic · CK Tech Check