the defect looks very familiar - since you provided more pictures to me in private eMail, I also know which trace exactly is burned on the bottom side of the IDE-fix board. It clearly indicates that the harddrive (or cable=>short) has pulled way too much power. I am assuming that you have made a wrong connection (as someone else in this thread noted: staggered connection), and made a short.
The picture of your burnt scandoubler also points at a defective or overloaded power supply. A dead MACH chip normally doesn't crack it's package like yours - there's some serious noise required on the +5V line to cause a latchup (which requires burning the latchup-protection of the chips!). You should check proper grounding of your in-house wiring, as this can cause bad noise on just about everything.
Jens Schönfeld
