LEAR SIEGLER ADM-3A

This is a blue version of the famous Lear Siegler ADM-3 terminal that was the prize possession of early home computer owners; the poorer ones had to build their own terminal from scratch if they could. Although it was quite expensive ($1000 in kit form), it was the least expensive computer terminal available in the mid 1970's. Consider that one could get an inexpensive new car for $3500 in 1976. The first version did not even have lower case capability; My -3A, built near the end of the run in the early 80's, does have this option installed. The dot matrix is only 5x7 and the lower case characters aren't on the same baseline as upper case characters, giving a "unique" appearance to the text. The CRT is black and white. The often-missing "LSI" plate was replaced with a piece of metal with the LSI logo printed on it. Very, very limited cursor control is available. I later obtained another unit that I restored, but it didn't have a lower case option, so I cloned it (link here).

The terminal has a very clever clamshell design (see below). The electronics consist of a monitor/power module and an extremely large PCB full of vast numbers of TTL chips. 2102's are used for RAM, and 2513's are used as character generators, separate units for upper and lower case.

It was in good physical shape, but the CRT was very dim and had severe burn-in when I received it; I replaced the tube for only $50.00! I absolutely hate replacing CRT's because of it's "exciting" nature (i.e., high voltage and implosions). Instructions for those bold and/or crazy enough to attempt this are here.