Head alignment for legacy Sony FDD

Hi, I've been trying to create a working Sony MPF50W (as found in the HP1650B logic analyser) from 2 damaged units. One unit had a fried board and the other unit had physically damaged heads. I moved the heads and track 0 sensor from the fried board to the other board and I need to do 2 things: a) confirm that the "new" heads are actually working and b) realign the track 0 sensor. I'm reasonably sure that the heads are okay, they show continuity on some of the pins, but I'm not 100% certain that is what I should be expecting. I can't find any obvious sources of information on where to probe to see useful signals from the heads or find any procedure to align the sensor. I have Tony Duel's diagrams of the HP9114 from hpmuseum.net . Any suggestions on where to find this information or how go about this would be really appreciated. Many thanks Peter