I bought a Joust boardset declared 100% working.
When I tested it all the coin inputs didn’t work
I ran the test and infact they were all activated
I was not worried because I was sure it was the 6821P PIA on the romboard.
After replacing it didn’t fix the problem.
Looking at the schematic there are also some 4066 CMOS chips involved.
I desoldered the one used by the three coins inputs and after testing it on my programmer it was declared good.
I decided to add a socket and test another one on board
Luckily the problem was fixed and it turns out my programmer is not reliable in testing CMOS devices.