I am new here, so first of all greetings to all!
I have a Korg DDM-110 which is completely dead other than the power led which lights up when I turn it on. I’ve poked around the machine and it seems the IC7 labelled TC40H393Pis dead. Strangely enough, the pins 7 and 12 of the TC40H393P should be connected to ground according to the service manual available online, but 12 is only connected to the ground on the left hand part of the board (for instance, the casing of the power switch) but not on the right hand side, like any of the grounds of the output jacks. Also, pins 1, 2, 7 and 10 of TC40H393P seem to be connected to ground on both sides of the board. The capacitors C19, C55, C57, C58 and C59 show 0V in circuit, so I am sure power is cut off somewhere on the board or all these caps really died. I tried to test ESR but I get strange values so I think I will just replace them all, the ESR tester is probably not calibrated. But, since my portable oscilloscope died I don’t know how to actually test the IC.
Since these IC’s can only be bought in bulk on the internet, I was hoping someone might have one laying around?