The clock boards were completely rebuilt; particularly challenging was the connector between the boards as it was beyond salvaging and I couldn't find a replacement. I tried hard wiring the two boards but the wires kept breaking at the board joint. Fortunately I stumbled across the replacement connector parts at Great Plains Electrical when I was looking for a kit to rebuild the DMD high voltage section (
http://www.greatplainselectronics.com/search.asp?pg=1&stext=twilight+zone&sprice=&stype=&scat= ).
I was then left with a clock that worked fine, but only once the pin had warmed up. That made it a bit of a challenge to troubleshoot but eventually I tracked the problem to a faulty opto isolator chip on the motor controller board thanks to a bit of help from an old post on rgp.
I also replaced the clock lights with 'straw hat' led's which have a better light distribution than standard 'cone' led's and which generate less heat than the original bulbs.
