Assembly day one - ICs, capacitors, power check, transistors installed, beginning on resistors

 POWER SECTION TEST

I soldered on the decoupling and filtering capacitors to the board and then installed the PC power supply connector. After validating correctness of the lines, I plugged in a power supply and it came up with all the proper voltages on the power rails. 

DRIVER INTEGRATED CIRCUITS INSTALLED

The driver circuits for signals going out to the IBM 1130 processor make use of surface mount sized 74LS06 chips, hex open circuit inverters. I soldered these down to the board and inspected the connections.

RECEIVER CIRCUIT TRANSISTORS INSTALLED

The receiver circuits for signals coming from the IBM 1130 are implemented with one transistor and six resistors apiece. I designed this with moderate sized surface mount parts, SOT-23-3 for the transistor and 0805 for the resistors. I soldered the transistors into all 36 circuits.

MECHANICAL FIT TESTING

I checked that the header pins line up properly with the FPGA board. I tested the fit of various connectors, one bringing 24VAC from the 1130 as power sequencing voltage, another two implementing SPI links, and the heat sink clearance for the 3V regulator (since PC powers supplies produce 3.3V, not the 3.0V that is used with SLT logic). 

BEGINNING INSTALLATION OF RESISTORS IN THE RECEIVER CIRCUITS

The output of each receiver circuit is coupled through a 500 ohm resistor to an input pin of the FPGA. I began soldering these resistors on the board and go about 2/3 through it by the time I had to close up shop.