Was HP 7914 - Priam 15050 & 3350s

Actually IIRC the HP 7914 has a Priam 15050 single platter(?) hard drive with a 14 inch platter. The HP 7912 used the similar Priam 6650 drive. These were used in many early computers from the late 70s to early 80s. Early Xerox 8010 Stars had them so there may be some info on the drives on Al Kossow's Site. IIRC these auto head park (with a loud clunk) when powered off. There may be drive &/or head locks too. I am looking for information on starting up some Priam 3350s, 8 inch HD drives. I have an Intel 330 (6 slot Multibus 1) and an Intel 380 (14 Slot Multibus 1 with separate drive cabinet) that I want to fire up before I part with them. Both these use Priam 3350s. Also looking for ideas on how to start them safely. Last time I used them was about 1989. I did park the heads and locked the drives for the intervening years. Paxton Astoria, OR