Today I soldered together more lamp assemblies, eight at a time with breaks to minimize frustration and achy backs. By the end of the day the main board had all its 96 light positions installed. Now that the big board is done, there are a mere 60 to build for installation across the two small boards.
RELAY TESTER BUILD FOR TECHWORKS!
I received all the remaining parts today and began layout of the components inside the project box. I marked up the holes to mount the two relay sockets as well. I located my 20V and 5V power bricks which will drive the coil and contact current.
The design uses 1W resistors to control current through all the contacts, developing about 150 ma on each set and measures the voltage drop of the contacts to determine quality. Small Arduino interface relays fire the 20V pick and hold coils on the relays under test.
I will solder the 1W resistors directly onto the relay sockets, so save the space required for a resistor mounting perfboard as used in the original machine. Thus I just need to mount an Arduino, a small relay board, the two relay sockets, and four LEDs. The two power bricks and most of the USB cable will be outside the project box.