Finishing new PCB for 1130 MRAM, waiting on memory chip

CONNECTOR PINS INSTALLED AND MORE CHECKING ON THE PCB

I use square profile gold plated pins, soldered onto the PCB with the correct spacing, to form the SLT connector into which the three cables from the 1130 system will plug. A spare cable socket held under the PCB lets me orient the pins correctly as I insert them and solder them down. 

Everything but the memory chip is installed

I did more checking of the solder joints to the chips and connectivity of the key circuits. Using an external testing box I inserted a rising edge on the +Storage Read and +Storage Write pins, which allowed me to watch for the proper timer output pulses. They looked good.

Without the MRAM memory chip installed, the NAND gates that produce the sense bit outputs will see every bit of a memory word as a logic 1, thus each sense bit should produce an output pulse when I drive a rising edge on +Storage Read. Using the oscilloscope, I verified that this occurred as intended. I found a couple of anomalies to investigate. 

It also allowed me to verify that the parity generation circuitry would produce a parity bit value of 1 for both halves of the word, since each halfword had an even number of 1 bits (8) and the 1130 uses odd parity checking. 

WAITING FOR THE MRAM MEMORY CHIP FROM DIGIKEY

The shipment from Digikey is expected to arrive late Friday. I will be away visiting family (again) for a few days but by the end of the weekend I can get this soldered onto the new board.