Mark,

I had an issue that sounded like yours......
All bands would output what they should ie 100w with the exception of 6m.

I wound it up in the settings and still couldnt reach 100w for 6m

I later heard a bang then some smoke mid way through a contact on 6m - thought the worst. Pulled the 100D ...

I have been out done.....

Well done on your solution Philip. Extraordinary transplant.