I don't know why but I just had to have one of these
got it on ebay 11/17/2013
here is the cropped original ebay pic

HA-14 Manual
HA-14 Full Manual
Schematic

HP-14 Manual

Schematic

HP-24 Manual

Schematic

ok here are a few pics of how it came to me

for a full size image click on the pic

E Mail