New MK2 - works great - but doesn't like CPU

Hi All,

I received a brand new MK2 to start 2022, plugged in chips, and powered up using the icomp power supply. Everything works great, but the Diagnose LED keeps blinking. Connecting via USB and using serial port connection, I can see:

Error: CPU is not recognized, check U7
VIC-II: 6567 (B9 4D 9880 NTSC)

SID 1 : 6581 (9B C9)

SID 2 : Unknown (0000)

MCU : 20180227

READY (press key for menu)

I've tested with 2 different CPUs:

MOS, 6510 CBM, 4983

MOS, 6510 CBM, 1583

Everything seems to work great when using the MK2 with both of the above CPUs. Placing both CPUs in other C64s (before and after using in MK2) results in happy, working machines.

Curious if anyone else has run into this or has recommendations for other tests I should do. Any way to see move verbose error on the CPU check?

Thank you, Chris

I tried a third, working 6510 cpu. The MK2 board works great, but the diagnosis light continues flashing and the serial connection still informs me to check U7. Next, I took the cleanest of the three cpus and did the suggested scratch maneuver, but the board's diagnosis light continued blinking. Then, I gave the chip's pins a bath in DeoxIT D5, but sadly the board still doesn't like the cpu.

Aside from the flashing diagnosis light, everything I've done with the MK2 works perfectly (keyboard, cartridge, A/V port, userport). I'm just going to continue using it as my primary machine. If any functionality beyond diagnosis ever does fail for me, I'll let you know. Also, if I do find something that causes the diagnosis check to start liking my 6510's, I'll of course share my findings here.

Thank you for the above suggestion and thank you so much for making these very cool MK2s.