Diagnostic Tests Passed
Having repaired the ALU fault, the diagnostic microcodes were run again.
DISPKEY
DISPLAY8 generated a stable display, showing that a very basic microcode process could run.
KEYTEST correctly reported keycodes and correctly counted keystrokes.
ALUtest
All ALU subtests returned the expected results, confirming proper ALU function restored.
MEMTEST
This confirmed that all 4k of RAM was writeable and readable.
Calculator Microcode Test
Running original MOS ROM
With all above tests passed it was reasonable to proceed to a trial of a known good 4K microcode in the DoPECC ROM emulator. This produced a functioning Wang 600 calculator!
Printer and tape will require some attention and then a more complete set of functional tests will be done but at this stage it appears that the machine has been repaired.
Test with MOS Microcode ROM
Reinstalling the machine’s original MOS Microcode ROM also gave a functional machine, enabling the machine to be fully complete and functional.