TV Typewriter II

Hi all, Now that my SWTPc is running (and with a floppy disk running Flex 2) , I am working on restoring its original terminal, the famous TV Typewriter II. For those who don't know, this was the first home hobbyist computer terminal. It was actually developed before the first micro, and was the only inexpensive terminal available for the first micros. This second version was a reworking of the concept originally introduced by Don Lancaster. In any event, mine is not working. No video output. Some of the circuitry involving the sync generation, where the timers, diodes and AC reference signal are involved, seems to be amiss. Thanks to Michael Holley, I have the schematics and construction directions, but there really is no diagnostic help. My problem is I don't know where to start. On a computer, you have a processor, and known things happen when you hit the reset button. The TV Typewriter is mostly TTL logic, and has no processor. So, it really doesn't do anything when you turn it on. Any suggestions as to how to go about diagnosing such a beast would be appreciated. Louis