I found my old Black Hole clock in the attic, and it's tubes were burned out. But there is a fix!
So, if you have a Kirsh-Hamilton Prisma or Black Hole clock, and the old fluorescent tubes are out, I'm offering a simple LED strip replacement. This is not the new $300 LED board, but will get your clock working just like new except with daylight LEDs instead of those two fluorescent tubes.
While I'll disassemble the clock with care, note that because these clocks can be decades old and old plastic parts can break. Usually this is the little plastic triangles that the screws go into, and they can be glued back and should work fine.
A 12V power supply fits neatly next to the clock module in the back, and the LEDs are affixed where the tubes were, and it works well.
Please call or email before sending me you clock!