Mixsonian Larry


IMSAI 8080

IMSAI 8080

My new job was supposed to start the following Monday so I had a couple days to get settled in to my new place but also giving me time to start assembling my IMSAI 8080.  I opened up the box again and started laying out all the components in an organized manner on my worktable.  There were lots of parts for I had bought everything in kit form.  This wasn’t just a simple a simple assembly project, each of the computer boards for the system came as a kit, bare circuit board, computer chips, resistors can capacitors, thousands of parts, each had to be soldered individual on each card. 

IMSAI 8080Inside the IMSAI 8080, cards and card slots on the left, power supply on the right.

The main computer itself had two dozen switches, three dozen LED lights that had to be assembled and soldered.  The main computer board had 22 slots for the computer boards, each with a 100 pin connector. There was a huge power supply that had to be assembled.  Then there were the cards for the computer.

The 4K memory cards were the worse, they had 52, 16 pin Integrated Circuit (IC) chips which each pin had to be soldered, over 800 solder points alone, then there were many resistors, capacitors, LEDs and other items, over a thousand solder points total, and I had two memory cards.  The CPU board, I/O boards, cassette interface boards were not as bad but still had hundreds of solder points.  Each solder point had to be precise or the board wouldn’t work so I spent many hours soldering. Ah! The smell of burning solder rosin I remember so well.

IMSAI 4K Memory cardIMSAI SIO card

I did not get it done in a few days like I had intended, It took me several weeks to get everything put together and assembled.  In the meantime, I had a new job to start.  

Updated: 03-01-2023

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