DSD Diags disk found

Analogue alignment disks exist (AFAIK) for all floppy drive siszes and demountale hard disks. I have a few, I'd likle to find the 8" and 3" (not 3.5") floppy ones though. But not at the 'new' price :-) They were all pretty much the same. You move the heads to the right cylinder and connect a 'scope to the outputs of the read amplifier. Trigger the 'scope off the index pulse and adjust the head position until the 2 lobes of the patter are the same size. The problem (for many people) is that you need a 'scope. I have a thing called a 'Microtest' which allows you to do a disk alignment using an _analogue_ aligment disk but no 'scope. It needs a PC (according to the manual, the minimum spec is 256K RAM, 1 serial port, any type of display adapter). The unit is a little box containing a microcontroller (8035 IIRC) and an ADC, which is linked to the serial port on the PCB. YOu cable the drive up to the PC as drive B: and run the speical software supplied. You select the drive type from a menu and it shows a diagram (drawn with IBM liue drawing characters) of the drive PCB showing where to connect 5 leads from the ADC box to the drive (IIRC these are the differential outputw of the read amplifier, ground, index pulse, and track 0 sensor). And then you put in the alignment disk and run through a seires of tests (motor speed, raidal alignment, track 0 sensor position, and so on). I find it works quite well. I've modified an old Amstrad PPC640 'laptop; to have a DC37 socket in place of the second floppy drive. I can then connect the drive under test to this,. plug in the Microtest and do the alignnmet. One tip. If you have a drive that's probably fairly well aligned but which you intend to dismantle, repair and then have to realign, mark the positions of the track 0 sensor, index sensor, hard posiitoner, etc before you remocve them. I've been known to step the hard to cylinder 0 on an exerciser (provided the drive still basically works) and measure the clearance etween the head carriage and the stop with feeler guages, for example). Then when you reassmble, put things back in as close to the original position as you can/ This will not be accurate enough to be properly aligned, but it will be near enough that you can detect the alignment pattern. Otherwise you can find youself moving the heads all over the place in an attempt to find even a trace of the pattern. I would be very interested to find that out :-) -tony