Thanks for all the advice everyone.
Indeed the set must have belonged to a smoker, now deceased as it came from the cupboard of a house that was being cleared. Every single board on the chassis was a tarry mess. I've removed each individual board and thoroughly cleaned, re-capped and reflowed each one. Just finished re-capping and reflowing the main chassis over the weekend.
The tripler was horrendous, absolutely covered in a thick tar, took ages to clean off but I have a couple of NOS ones if necessary.
Hopefully be able to get it back together this week fingers crossed. Pictures to follow.
Incidentally does anyone happen to have a spare Tuning Module, part no 29504-003.02 as the backup battery has caused more damage than I had thought, quite severe corrosion to both sides of the board and traces. I can probably patch it up if all else fails
