Reparing a Boss PS-5 SUPER Shifter

[VintageGear]

Quick question! Got a burned PS-5 on the workbench. Already replaced the IC8 (S-8520E33MC), a 3.3v stepdown PWM, but anybody got a source for a 2sj190 (Q12)?  Can't seem to order it anymore!

On the other hand; what's the point of having that mosfet there? Couldn't I just replace it with any other mosfet? Help me understand please :-)
(found image on an OC-3 thread which seems to have similarities in power supply)

Or; why not just put in a 'normal' 3.3v regulator?
Help is appreciated once again :-)

edit: fixed image..

[VintageGear]

Fixed the image, was no longer working.
What would you guys suggest?
1) Fit in any p-channel MOSFET?
2) Pull the IC8 and put in a 3v3 regulator?

[VintageGear]

Answering my own question as I had a 3v3 regulator laying around: Yes it gets 3.3v on the rail, but the pedal aint responding unfortunately. Something else went p0000f. Being all digital, this one goes into the parts bin. No datasheets on the Boss chips to found on the internetz unfortunately.