Monday, May 6, 2019

DSKY closed up and ready for testing with a purpose built test rig



After detailed examination of the space available inside the DSKY enclosure, I decided that there was insufficient space to arrange the power board - boost converter, relay and EL driver module - without compromising the remaining components. I therefore decided to mount this board externally, on the outside bottom of the enclosure.

I was ready to assemble when I detected that one lead of the cable to the EL wire had broken loose. That needed to be repaired before I could install the display board with all its cabling. It was soon fixed.

The display PCB was screwed into place inside the enclosure. I did the epoxy gluing of the light dam over the PCB, then worked on covers and panels to get them glued together and onto the faceplate. Now that everything fits together nicely, I can put on the front screws and some mounting standoffs on the  bottom of the enclosure, to complete the physical construction.


I had designed a test fixture driven by an Arduino Uno, leveraging 24 relays and other circuitry to act in place of the Apollo Guidance Computer, sending control signals to the DSKY and receiving the results of operator keypresses. I had to wire this up and set up a triple power supply with 5V, 14V and 28V sources that are required by the DSKY substitute.

A real DSKY would have 28V and 14V, as well as 115V 400Hz AC, but not 5V. That last voltage is needed to power my modern components inside the DSKY substitute. The 115V supply illuminates bulbs under the keycaps of the real DSKY, but is not used on my implementation.

I began wiring together the relays in the text fixture and connecting it to the DSKY cables. 

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