Panasonic HHC ROM 'capules'

[Jeff_Birt]

I had thought the HHC must poll each ROM socket at power on to determine if a ROM is present. Looking at a manual for a capsule it does seem like this is the case. I set the scope up to trigger on a rising edge looking at the VCC on each socket and...nothing. Very odd. I'll need to pull the back cover off to delve deeper into it. When I get the newly ordered capsules in, I can test on of those in this HHC.

BTW, I confirmed I found the VSS pin of the socket by measuring from it to the /RESET of the 6502. I could capture the /RESET rise after power was switched on. Measuring to the address and data bus pins reveals toggling but I did not specifically test A13 so see if it went low briefly at power on, that would have been a good test.