The Four Phase IV/90 at MITA -

We are not really sure how many Four Phase systems were produced. This one is serial number 8603. But as nearly as we can tell there about six left in the world, so we consider it quite a prize.

We ran some smoke tests on the IV/70 chassis with a IV/70 CPU card. We then turned on a monitor. Finally we turned on the CPU with the monitor connected. The results were very pleasing. They are shown in the last four pictures below.

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Four Phase Systems IV/90

IV/70 chassis from the IV/90





Data and Alarm Jumpers

I/O & CPU cards

Video RAM and CG cards

Keyboard Template


Video cable ends



Smoke Test Number 1

Smoke Test Number 2

Smoke Test Number 3 A

Smoke Test Number 3 B


Information on the world's first microprocessor. Hint - it's not the Intel 4004!


Intel's page on the 4004Notice it says "Intel's First Microprocessor—the Intel® 4004"