Hi Jeffrey,
The clean I did was purely a hoover with fine nozzle and an artist brush, nothing more, so i'm confident i did not disturb it. The set according to the previous owner went to bed in 1980 and by the looks of it the fluff blanket kept things nice and insulated
If the build date stamp on the LOPT is also the set's date then it was in service for 22 years before that, maybe the PL81 that had failed was why it went to bed.
Just waiting for the PL81 to arrive and then I'm back in business following your advice of Friday/Saturday.
Hope to see a test card on it like some of the other posts, In the meantime i'm sticking my head back inside another DAC90a..... I just love Bush's
Chris