I cleaned my keyboard after a few years. I was using a steam cleaner… Yes, daft. While the board no longer works it is clean!
When I opened her up to see what might be wrong, I noticed “gunk” and charring on the U1 MK22FN512VLH12 (square chip). Despite cleaning up the contacts and ensuring there were no shorts, the board is not working. I suspect that replacing the chip will do the job.
The board is: UHK60 v7.8 04128 2019/07/09
I ordered to part from mouser.
Can I just replace the part or does it need to be programmed/flashed?
Finally, any guidance on what/how to test the circuitry to validate the diagnosis would be greatly appreciated.
If you’re not familiar with microcontrollers or don’t have a J-Link probe, I suggest a recall, although depending on the condition of your UHK, we don’t guarantee that we can fix it.
Thank you for the reply. I am familiar with flashing although I might not have a J-Link probe. The condition of the board is actually quite good. There is minor surface rust on the steel chase. The electronics seem to be in good shape despite the scenario I’m in.
It looks like the J-link programmer can be expensive. Is there a way to order a pre-programmed U1 chip from you?.. or maybe you have an old basic version of the programmer lying around?
I’m sorry, but we don’t have a spare J-Link or a pre-programmed chip. Such endeavors usually turn out to be very time-consuming, so I suggest a recall.
The supplier at Segger is very fair. The educational version of the mini was $60.00 (plus $25.00 for shipping).
Mouser is a reliable supplier of the processor - $20.00 including shipping.
The rest is on me. I need to use my heat gun to remove the old component and paste on the new one.
Any guidance or tips from experience here would be great!
To start: Any photos for how to align the J-link pins with the keyboard would be great.
The “1” pin on the programmer is not obviously aligning with what I’m seeing on the keyboard.
If I attach the pin from the top of the board (accessible by way of a notch in the steel chassis), it fits nice and firmly. However, when I align the pin “1” with the j-link, the orientation seems wrong - see the photo.
Despite confirming the connectivity of many of the leads, I was not able to get the programmer to connect with the processor. Somewhere it seems I’m losing voltage - I’m at 0.87V despite confirming close to 5V power supply.
./update-bootloader.sh
SEGGER J-Link Commander V6.20e (Compiled Oct 6 2017 17:06:32)
DLL version V6.20e, compiled Oct 6 2017 17:06:22
J-Link Commander will now exit on Error
Script file read successfully.
Processing script file...
J-Link connection not established yet but required for command.
Connecting to J-Link via USB...O.K.
Firmware: J-Link EDU Mini V1 compiled Dec 4 2024 17:56:44
Hardware version: V1.00
S/N: 801055499
License(s): FlashBP, GDB
VTref = 0.870V
Selecting 4000 kHz as target interface speed
Unlocking device...ERROR: Read from DP/AP register failed!
Script processing completed.
Your steam cleaner may have caused all kinds of issues, and we don’t have the capacity to troubleshoot them. Other forum members are welcome to help, of course.
