Korg ex-800 repair

[Kosmomishka]

Hello circuit benders. I am having hard time trying to install hawk 800 mod in ex-800.
I want to check power, but I never did it.
As I understand, I need to put black multimeter probe to ground.
And red to points on the photo.

Am I right?

Does it matter what ground point I will choose? Can I just put probe on chasis, as it seems ground going there.

[Circuitbenders]

I'd use the ground point on the top left, up by the power input where theres that black wire that connects to the cardboard ground shields. The chassis bolt would probably do, or the metal body of any of the switches on the back panel, but the probe will get a better contact on solder.

make sure you have the negative side of C11 for the -5v

[Kosmomishka]

Thank you for reply!

There is -5V after c11. And nothing where +5V should be.
I am confused how can it be caused by Hawk board. As with original IC22 and IC29 it powers on. I checked board and cables twice. Shouldn`t there be at least power on motherboard if Hawk board not working?

[Circuitbenders]

i think you might see 0v on the 5v rail if something on the hawk installation has shorted the power rail to ground.

Are you saying the EX800 works fine when you disconnect the hawk800?

[Kosmomishka]

The short story is:
It worked totally fine before installation.
Installed Hawk board, not power on.
Deattached Hawk board and installed original IC22 and IC29, it powers on, but have some issues (not working low octaves on DCO, waveform switch not working (actually it sounds like a mix of both),no Midi In (I tested it with internal sequencer). I think it is because I somehow damaged original IC22 and IC29 (it was hard to desolder them, and maybe overheated a bit, broke couple pins, and made jumpers from IC to board).

[lazydog]

have you asked Mike on Korgpolyex usergroup? Gordon appears there as well;