1802 Memory Test
I wrote this memory test program while restoring an ELF II 4K ram board. I've included the ASM as well as the HEX file which was compiled using Michael Kohn's excellent light-weight assemblers.
December 2023
October 2023
Scott Pack Microboard Build - Backplane (MB1802)
I recently became interested in building an RCA 1802 Microboard computer. My ultimate goal is to build a figForth based 1802 using mass storage for the word pages. I had built one back in the late 70's based on my own 44 pin back plane, Vector 44 pin plug boards and a FD controller I designed on one of the Microboards. It ran figForth quite well, but unfortunately this unit was lost to moves and life changes! I want to duplicate the function I had back then but using RCA's microboard backplane design.
August 2023
Netronics Power Supply
First of all I didn't know these even existed!
Netronics Giant Board
Lots of modifications to the Giant Board, mostly in back-side modifications that brought power out to the I/O port headers. All of that was removed and the board restored to factory configuration. C1 had been replaces with a .1uF and C4 was cold soldered and it's leads moving within the solder joints. Both C1 and C4 were replaced with .15uF caps, per factory specs. All jumpers were also returned to factory specs.
Netronics 4K Restoration
The 4K board was in better condition than the main board, but still has some very bad solder joints. It had been configured for on-board 7805 regulation using 8V from the bus, but that regulator was previously removed and the board reconfigured for using 5V from the main board regulator. This board draws 600 mA and so it is within the capabilities for the main board regulator to support it, The PC lands in the regulator area had partially lifted due to excessive used in the modifications done to it. The electrolytics were replaced and the board cleaned up.
Netronics ELF II Main Board Restoration
The condition of the main board was poor, with many bad soldering joints, and hacks that were done to it... Note the missing 2101 RAM ICs, missing D9 (normal since this restoration includes a 4K RAM board and a Giant Board), R2 is broken, and the unusual heat sink added with the PCB under it displaying significant heat damage!
SBC1802
This is my single board 1802 build with full address display, configurable output port display, hex keypad display, 32KB of ram, 32K EEPROM, and all status/control lines displayed.