I have been collecting vintage 6 digit clocks for about 2 years now and I may be having to admit that a problem may be starting . I enjoy the vintage kits from the 70's hobby magazines as well as some production models or even vintage homemade of the time. I wanted to mention if anyone had MM5314N driven clocks that they were done enjoying or are not functioning, I could give them a good home. 7400 series TTL clocks are welcome as well. USA types are better but conversion is usually possible.
If anyone visiting this post is curious or would like to see these types of clocks, you can always visit JIMO415 on Youtube for basic documenting videos of various types.