Danny said "Coke machines in Towers! What next! Ain't tea good enough for the likes of us? What are WRAF Assistants there for except to brew tea for the Lords of the Universe? Who got the profit from the machines? NAAFI, I'll be bound!"
No idea who operated the system, but Coke machines were everywhere at Tengah: 20 cents a nicely chilled bottle, IIRC. I don't think we had any WRAF Assistants: our Tower 'cleaner and gofer', Frank Goh, did the brews, and would pop downstairs to get your Coke if you were stuck on a console.
Fareastdriver quoted ... "Printed Circuit Board Manufacturing - Making PCB Holes Conductive ".
That sounds like the issue! It dried like a brown varnish on the circuitry.