This is one of those repairs that reveals something… in this case a manufacturing defect.
My WOZ started smoking one night and then stopped working. After examination, we found this..
What apparently happened was a choke/coil on the power supply board overheated and failed, taking out miscellaneous other components with it. This happened around the same time I did a new software update, so I was concerned it might have been triggered by software, but upon further investigation, this was not the case and just a coincidence.
Upon talking with the folks at JJP, they are aware of the problem and it’s a defect in the power supply board, using an under-powered choke. Supposedly they fixed this but some games got out with the old choke. It’s not a question of “if” it will fry, but “when.” What’s worse is, if this goes out, it apparently has a tendency of taking out numerous other boards including the CPU and the display driver board.
You can see the difference in the size of the choke on the newer (left) power supply board verses the older one (on the right).
Unfortunately, for many of us, the game is likely to be out of warranty by the time you find out you have the old board. You should check and see, and contact JJP before it costs you much more. They may replace boards even if they’re out of warranty.