"Expensive" PC keyboard - ERROR 43 (software solution impossible)

[Kikerumbo]

Greetings,

I've been fighting with this keyboard for weeks and as a last resort I'll try to dive into the beast "guts", with your help I hope. I wouldn't try to repair it if it wasn't because it costed me +200€.

The issue is that not one of the 7 different PCs I tried recognize the keyboard. Always an ERROR 43 code is shown. Keyboard LEDs turn on, but it doesn't work. I've already done everything I can "software side". No drivers, different drivers, specific software from the manufacturer. Same result. The manufacturer, ROCCAT, has an utility for flashing firmware but is doesn't even show the keyboard when I try to use it.

So... now I'm here.

Would anyone know where to go from here? I see various SMD, like the ARM processor, the CMOS and 3 others that when I search for the code number, nothing is shown. Swapping the CMOS is doable (with my low level of soldering skills) and cheap (around 2€). But I'm "alone in the dark" since I don't know if the CMOS is the issue or how to test it.

I know wiring is ok, connectors too (USB and the inner ones) because I did a continuity test with a multimeter.

Pictures show the "innards".

Thanks in advance to anyone willing to help.

Have a good day!

[fable]

Hi I'll try to help...first you need to see if there are some components between USB data lines and MCU if there is not the most probably MCU is damaged. However if there are some, those components if faulty  can block communication.

[fzabkar]

Check the continuity of the L2 choke near the USB connector.

Also check the outputs of the LDO regulators (U1 & U4).

AN32181B, Panasonic, 12 x 12 Dots Matrix LED Driver LSI, 5V, QFN-28:
http://pdf.datasheetcatalog.com/datasheets/panasonic/AN32181B.pdf

MX25L1606E, Macronix, 16M-bit [x 1 / x 2] CMOS serial flash, 2.7V - 3.6V, SOP-8L:
https://datasheet.octopart.com/MX25L1606EM1I-12G-Macronix-datasheet-12510710.pdf

LPC1752FBD80, NXP, Cortex-M3 microcontroller, 64KB flash, 3.3V, LQFP80:
https://www.nxp.com/docs/en/data-sheet/LPC1759_58_56_54_52_51.pdf

UR133AL, UTC, 300/500mA LOW DROPOUT LINEAR VOLTAGE REGULATOR, SOT-89:
http://www.utc-ic.com/uploadfile/2011/0902/20110902012023486.pdf

[NiHaoMike]

Using another keyboard, run "sudo dmesg -c", then plug in the problem keyboard and run "sudo dmesg" after a few seconds. That will tell if it's it's trying to communicate on USB at all.