The Color Vectrex! (Prototype is property of Jay Smith, founder and president of Western Technologies/Smith Engineering)
Back in 1982, GCE was going to continue with the Vectrex line by adding a color version of it (and they even planned a handheld using a flat-type like in the Sony Watchman TVs, but that never went past the idea stage). A prototype color Vectrex was built, but Milton Bradley decided it was time to give up on it, and it was never put into production. The color prototype is actually a normal Vectrex with a few modifications (the obvious of course being the CRT itself). Rather than going with the expensive 3-gun type of color display (like in color vector arcade games), they devised a way to get color out a single-gun tube without a shadow mask (yeah, this may be a bit techinical if you don't understand how CRTs work, just trust me that this was an inexpensive alternative, and one never used before...). Basically, there are two different layers of phosphor on the screen of the tube (one red and one green), and the electron beam will light up one or the other by making a fine adjustment in the voltage supplied to the electron gun. A third color could be generated by applying just the right voltage to make both layers of phosphor light up. Really an ingenious design, it's too bad it never went into production. Unfortunately during this time of design and prototyping, the voltage got turned up a little too high on the electron gun, and the beam burned a hole (and a small line) in the center of the display. Fortunately, the tube still works, it will just always have this burned spot in the middle of the screen. Click here to see pics of it operating in two different colors! Unfortunately the tube most likely can not be replaced as it was a one-of-a-kind engineering sample for GCE using a techinique that I don't believe was ever used again.
One of the other changes to the Vectrex is the high-voltage rectifier (seen mounted to the top of the case in the picture with the large red wire coming out of it. Notice the silver box in the upper-left corner of the circuit board with the small white wire cut off, that's the original rectifier for the standard Vectrex CRT). The final change made was adding a little circuitry to the CPU that tells the power supply for the CRT which voltage level to use in order to get the appropriate colors. Naturally the Exec ROM is a little different as well (it's checksum is 51E0).
The picture below is an internal shot of the Color Vectrex. Note the new high-voltage rectifier for the color CRT mounted at the top of the case (with the red wire coming out). The small project board on the table contains two logic chips that are used to tell the CPU what color to display on the screen. There is also a second board which is basically a home-brew transformer to power the rectifier for the CRT. (You can barely see it, but the Exec ROM has a sticker with the Western Technology 'infinity' logo on it, and has the word 'Resident' handwritten on the label.)
Here's a closeup of the two add-on boards that were rigged up to make this work:
I also seriously believe that the Vectrex used to convert into
the color Vectrex was also an early prototype model. The circuit boards don't
match any I've ever seen in a Vectrex, and the design of them doesn't match
the service manual schematics. The obvious differences are that EVERY microchip
is socketed (even on the power board), the 'Mecca' ground trerminal is actually
used (there are at least 5 wires that go to it from different locations on
the power board), and the copper rails all around the logic board (which you
can sort of make out in the picture above). Also, on the power board are 5
large 15,000 uF capacitors, all the production models I've seen only have
4 (two 10,000 uF, and two 4,700 uF). The case is also obviously pre-production,
on the front it's missing the indented area where the Vectrex logo goes (above
the screen), and the back is missing the warning that is indented in the plastic
(see pic below:).
Prototype back compared with production back, notice all the
info beneath the sticker missing on the first case, where any production models
sold like this?
More pictures of this machine can be made available if there is any specific part of it anyone wants to see... Just send me an Email and I'll add them to this page.