I would double check the socket you installed with the NVRAM. WPC era boards have really thin traces and can be damaged easily when desoldering the RAM chip. Follow the trace from each pin of the socket to the next component along the trace. Check continuity from that point back to the contact in the socket. Check continuity between adjacent pins of the socket (looking for shorts).
Also double check the actual NVRAM installation in the socket. Make sure it is oriented correctly and all pins installed.
Matthews, NC
