Finally have this all working with stable PSU voltages, all the caps have been replaced on the PSU and logic board with tantalum ones, sound is back, running perfectly!
Fan was really noisy tried Sewing machine oil but just didn't work, so new low DB one should be here tomorrow, in the meantime stripped it down and gave it some retro brite treatment, disassembled the floppy and cleaned that.
The SCSI still works so going to use my old G4 powerbook and Imation SuperDisk drive which I found in my storage to format some old software but did find a case of my old 1.44 Floppies so should be fun going through that.