Mitronics Frequency Counter

[SvenVE6]

I figured it may be a good place to ask this question. Dr. google did not return any results on this one.

Mitronics MIC-1028 Frequency Counter... Ever heard about it? Scored one at a local flea market and one I got from a fellow HAM guy. One is working fine but the other has issues. As mentioned, no google infos available. 

Attached some pictures for the curious guys out there 

Very neat little unit and probably useful for quick measurements. Perhaps someone has some history about this company, schematics or anything else...