Roger,
That sounds like the issue I have at the moment. I've taken the bottom panel off and found that it's the mains suppressor unit that has gone and that's what sparks / makes the pop sound. When you take the panel off, look to the left side and you should see a small cylindrical object that is grey. You should find that it has split.
I'm current looking for one to replace it but the problem is that there seems to be an updated part available now that I'm trying to find out if wiring changes are needed.
Isaac
October 2011