I was struggling with my Twilight Zone clock optos big time, plus trying to find the original optos was a real pain
I got in contact with Ingo from germany who has made a replacement board that from what i can see is far superior to others out there. Installation is very easy, and instantly had my clock back working.
It is a single layer design, using a different (readily available) opto and driver system, as well as good LEDs to get rid of all the problems that come with the original boards.
I grabbed a few so have a couple of extra for sale
Ingo also made me a test bench where i can test the new boards before sending them out to ensure they work 100%, as well, it can test the old boards. My old board had 1 out of the 8 optos that tested reliably!
At the moment they come standard with warm white LEDs (which mimic the original bulbs very well) but i also have one set each of the following colours
Cool White
Green
Yellow
Red
These are $5 each for a set (4)
There is an option to get colour changing ones, but i would have to wait a few weeks to get some more of these - they are about an extra $15 (for set of 4)
The board itself is $125 including registered post anywhere in Australia
See below for pics
Testing the old board
Testing the new board with warm white LEDs
Testing new board with different LED options