Since my last post more hours have been expended on this old radio. To summarise :-
Numerous hours spent with the TS-180S connected to an aerial simply being a receiver. The purpose of this was fourfold ;
1) Get some hours on the clock to see if any further "corrosion related faults" arose (they didn't)
2) To evaluate the intrinsic frequency stability of the transceiver (it proved to be acceptable for the technology of the day)
3)To evaluate its performance as a receiver (it lacks sensitivity - a lack of IF stage gain is prime suspect)
4) Allow me to ponder how to tackle the lack of transmit output (there is a very small amount of RF transmitted, but I think I need to tackle the suspected IF gain issue first as part of the IF is used in the transmit chain)
Anyhow with all this input to my overloaded brain I resolved that the time had come to put this project on the back burner therefore allowing me to move other projects on as I perceived I was becoming somewhat obsessed with this one!
Having made that decision I decided I would reunite the radio with its covers, albeit temporarily, and that is when I noticed something I had missed. There on the bottom half of the case, on the inside was pretty conclusive evidence of some kind of "spill" which had pooled in the bottom of the case leaving a residue!
Ha! I think my earlier suspicions have been proved correct. Judging from the size of the marks inside the lid, it was clearly a sizable spill.
When I return to this project it will be armed with that knowledge, and I will need to bear in mind what other damage may have been done, and seriously consider what the chances are of a full restoration without a ridiculous amount of expense.