I thought it was kinda sad K8800 didn’t get a LED kit like the K8400, so i decided to give it some bling on my own
Yes, it has PWM.
No, it’s not Neopixels.
I’ve desoldered the beeper and its resistor (couldn’t hear it unless my face was practically in the printer anyways), as well as the pin 13 LED and its resistor, and reused those pins for G and B. Then i’ve soldered an enamel wire to one of the unused PWM pins on the Atmega 2560, immobilised it with hotglue, and soldered the R to that.
R, G, B and GND from the board go to a little piece of scrap veroboard with NPN transistors and resistors, that serves as the driver for the strips. The power comes from the unused 15V header, and goes through a DC-DC buck converter i had (incidentally, Velleman’s), tuned to about 9-10V so the strips don’t glare too much.
By the way, whoever designed the board for the K8800 wasn’t quite thinking straight - almost all of the PWM pins on the Atmega are unused, those that are used were used for silly things that don’t need PWM at all, and the extra unused GPIO header is all non-PWM pins, except for pin 5, which is a PWM pin, but not when using Marlin, since its timer is used for other things (namely, the stepper ISR). So wasteful.
PS: Please excuse the mess, i ran out of space on my workbench and ended up doing the final reassembly on the kitchen table.