EARLY ARRIVAL OF PCBS
The delivery estimate for the new version of the memory board was Friday afternoon, but I was pleasantly surprised to receive it early this afternoon (Thursday). That was the last part I was waiting for in order to build what is hopefully the final version of the board and put it into the IBM 1130 system.
BEGAN BUILDING NEW BOARD, INVOLVING MOVING PARTS ACROSS FROM OLD BOARD
The design has some new parts on it, both in the power supply area and for the Sense bit output circuits. I first installed the power supply and checked its operation before installing the rest of the circuitry. It gave me a reliable 3.3V supply for my circuits and isolates the ground when power is not applied so that there is no back feed of voltage from a partially ene...
EARLY ARRIVAL OF PCBS
The delivery estimate for the new version of the memory board was Friday afternoon, but I was pleasantly surprised to receive it early this afternoon (Thursday). That was the last part I was waiting for in order to build what is hopefully the final version of the board and put it into the IBM 1130 system.
BEGAN BUILDING NEW BOARD, INVOLVING MOVING PARTS ACROSS FROM OLD BOARD
The design has some new parts on it, both in the power supply area and for the Sense bit output circuits. I first installed the power supply and checked its operation before installing the rest of the circuitry. It gave me a reliable 3.3V supply for my circuits and isolates the ground when power is not applied so that there is no back feed of voltage from a partially energized 1130 into my board.
The bulk of the construction will take place tomorrow, but I was able to install two of the timer chips that produce an 80-100ns pulse delayed 800 ns from the trigger event of a write to memory. The timer chips are very small and a challenge to solder, but I got them on and validated good connectivity for each lead without any shorts to adjacent pins.
