Had my nose in a '57 Silvertone all day, then typing up invoices, then the feedbag.xtian wrote: Hoping to hear from Leo or someone on building an LED-based opto bug replacement.
I use a superbrite orange or yellow LED (Mouser, about a buck) and photocell sold as a Morley replacement by CE/Antique. Just put 'em in an inch of black HST. Long LED lead goes to the 100K & bobsyeruncle. I used to worry "high voltage" but these have lasted years so far, no breakdowns & no other mods.
Fender bugs, aging as they do, often the photocell becomes weak or one of the leads breaks loose. At the other end, the neon darkens with age, sometimes becomes weak, and often injects a tick into the audio.