Boss rc50 issues

[9 volts]

Hi there my boss rc50 seems to have died. All the LCD displays is arrow of black boxes. The system doesn't load when turned on. The voltages seem OK (3.3v to CPU) and the CPU crystals are are still working. I can't find any info online about this. Does anyone have any thoughts on what I should check? Thanks

[Digital Larry]

Don't know anything about it but I'd confirm that the CPU is getting a valid power on reset pulse and if there are memory chips or peripherals, see if there is bus activity or chip enables moving.