Needed: 1 IBM 8" alignment disk.

> I was hoping to use an alignment disk as this drive is filled with TTLs

Hmmm... As I mentioned in another message, _most_ alignment disks won't really help you here. What you want is a 'diagnostic' disk -- one filled with valid (and known/simple) data patters -- tracks of sectors of all 0's or all 1's, things like that. Fortunately, such a disk is fairly easy to make if you have any other machine with 8" drives. I normally use one of my CP/M boxes for this. Then you can conitunally read sectors from the disk. Using a 'scope you can see if the read PLL is locking -- is the read clock synchronised to the off-disk data. Once you've got that, you use a logic analyser (preferably) to look at the data stream and see if (for example) it detects address marks correctly (these are quite easy to recognise with a little practice. > pots... The manual has many test points with pictures using the alignment > disk. I have no idea if the IBM system diskettes I have actually have a

My guess is that _any_ disk will do for setting up the PLL. For other tests it helps if the data pattern is known and simple. -tony