Isd this one of the half-height units using many of the same parts as an Apple 800K drive? In other words similar to the drive used in the HP9114B? What was fried? I think, given the choice, I'd have prefered to keep the mechanics untouched (thus avoiding alignement problems) and chan ged components on the PCB. In theory if you change the heads, you need to do a radial alignment -- what most people mean by 'aligning a floppy drive). That said, I've replaced the heads in a full-height Sony (as used in the 9114A), put the alignment disk in and found it _well_ within spec. Maybe I was lucky, or maybe, as I suuspect knowing Sony, the units are made to a high degree of precision anyway. One thing worth rememebring : Almost all the adjustments are 'interchenagablity adjustments' to make the disks used in that drive compatible with others. If they're off, the drive can still format, read and write its own disks. So take a blank disk and try to format it. If it formats and verifies OK, or if it fails on the innermost few cylinders only (maybe the track 0 sensor is so far off that the innermost cylinders are 'off the end of the disk), then the heads are working. If it doens't, you've got other faults to find. If this is one of the drives covered in 'my' diagrams, I'll have shown the head connections there. A head winding will test as a very low resistance (dead short) on a meter. Just about the only thing that's not connected to anything lese is the screen (shield) The full-height Sony drives have the head switching diodes on the flexiprint to the heads, which might confuse your tests. The half-height ones have sepearate head tails from each head ans the swtiching diodes on the main PCB. If this is the drive I think it is, the analogue circuity is in one big ASIC. There's an LC filter circuit hung off that. looking at 2 'equivalent' pins of that with a differential-input 'scope will show the head signal. The normal way to alignt the track 0 sensor involves the euse of a drive exerchiser. What you do is move the sensor right out (to prevent it stopping theh eads from stepping out when they get to what thr drive things is track 0,), then, with 'standard' formatted disk in the drive, step out until the signal is lost (that's one cylinder past track 0), step in once, and move the sensor in until it just triggers. Then make sure that the track0 signal is asserted on track 0 and not on track 1. -tony