the DIP
switches don't work reliably any more
This is a problem with lots of 20+ year old DIP switches. They were
barely reliable when they were new.
I generally replaced with newer, high-quality (not 49cents!) DIP switches.
I was also disappointed that "normal operation" and "erase my disk"
were
nearby in DIP-switch space, so that a single failed contact could do in my
disk.
Vince