<Yes, I'd realised that. I was planning on making a circuit that triggered
<off the index pulse and recorded 'bursts' of (say) 250kHz pulses on the
<disk. A bit of logic would let me record a track offset towards the edge
<of the disk, twiddle the micrometer to move the head to the same offset
<towards the spindle and then record bursts between the ones I'd just put
<down. Now align the target drive so that both types of burst are replayed
<at the same amplitude.
doesn't work, you need the narrower write head. What you will see is
the additive components of the signals where the head overlaps the tracks.
The can be the sum or the signals, if not in sync there will also be
differences due the phases at a given instant. Also do not discount the
effects of the tunnel erase portion of the head slicing off the adjacent
offset tracks.
<The older SA800's used entirely standard logic, so it's not worth taking
<parts from an old one. SA850's used custom chips in the read/write
<circuit, and later SA800's (according to my service manual) used one big
<custom chip :-(. I guess then you have to get spares from old drives.
Sometimes it's easier to swap a known board that troubleshoot.
<Getting _new_ 8" drives is next-to-impossible, and if you use a
True but, there are used and then there are USED. The later being one thats
seen umpty years of 24x7.
<The less said about that SA400 the better....
Yep!
Allison
Received on Tue Aug 19 1997 - 09:13:29 BST