I was having an issue common to all with my TZ and the broken clock message. My TZ clock was working intermittently. I tried every fix I could find on the internet to no avail. I thought for once, darn it, I am stumped. I reached out to Ingo Kramer to try the German Clock boards he has developed. My results as follows.

I received the clock boards and they looked great. Very robust and manufactured nicely. Assembly was also a snap. Very easy to do. I reassembled the clock with these new boards. At first, the clock didn't work. I was still getting the intermittent failure. After reassessing, I applied the black electrical tape to the minute hand body between the hand and circular cotter pin. This pulled the body of the minute hand nice and snug against the optos / face of the clock. I reassembled, and the clock works perfectly. No issues what so ever. It has been running perfectly for one week now and looks great. In the end, my solution was to go with the German clock boards from Ingo along with tightening the slack in my clock. If you are experiencing issues with your clock try this. You will not be disappointed. Ingo was great to deal with. Also, if you have any slack in your clock where the minute hand falls slightly away from the optos, you must fix this for the clock to work. In my case the slack was so slight I thought for sure this would have no impact. In the end, this slightest amount of space was indeed causing the clock not to work. The electrical tape and new boards worked for me. Here is a link to Ingo's site if you are interested. Feel free to reach out to me if you have any questions on how to get your clock to work. I must have taken that clock apart and reassembled at least 6 times.

Thanks
dougram69

http://www.german-pinball-modular.de/final-tz-clock-pcb-english.html