Slow blinking (1 blink at a time) of the diagnostic led means ROM error, but can also indicate CPU not starting because of shorts in data or address bus. Re-check your soldering and look carefully that no PCB foils are broken either top or bottom of socket.

Misplacing the two connectors should not fry anything.

I have currently a CPU board on bench that does exactly the same. The board came without ROM and RAM sockets, but they were quite nicely removed with no apparent damage (don't know why). Installed new sockets, going to check address and data connectivity from RAM/ROM to CPU, and chip/page select signals from ASIC to ROM and RAM.

The ASIC itself fails very seldom, but the socket pins may bend inward so they do not make contact with ASIC pins. If you want to try with another ASIC or check the socket, be sure to use a proper PLCC removal tool - do not try with a screwdriver, that will only cause the socket frame to crack.

I have had some problems with NVRAMs in System 11 games, because of their quite strict tolerance of supply voltage. If the +5V is even a bit low and the battery isolation diode drops 200-300 mV, then the NVRAM refuses to operate. Since you dont need batteries anymore, try shorting D1. I have replaced them with selected low drop Schottky diodes with good results, but if you are sure the board will never have batteries installed, it may as well be shorted.

OK.

Might be my own memory failing and the low voltage problem did occur with Dallas DS1225 NVRAM, which I used before the FeRAM was widely available.