HP9817

A rather strange question : Was there ever an 68020 daughterboard for the HP9817 (aka HP9000/217)? The reason I ask is as follows. The HP9817 (I have one in bits on the bench at the moment) uses a 68010 processor. It's in a PGA pacakge, and is socketed. As the data sheet shows, it's a 10*10 PGA, with 2 rows of pins round the outside, and the 4 internal corner pins (a total of 68 pins). However the socket on the HP9817 board has all 100 contacts fitted. And some of the ones that don't correspond to pins on the 68010 have traces going to them. It appears these are extra intputs to the MMU circuit (in particular to the 'Tag RAM' for virtual memory paging). I am wondering, therefore, if the machine was designed to take a processor with more address lines brought out, the obvious candidate being the 68020. Of corse it would need a daughterboard to rearrange the pinout, but apart from that it may well drop straight in. -tony