physical is a .1 grid of square pins coming off of a flex cable to the head stack.
electrical is you supply a bias current and directly read magnetic flux with an opamp
I traced all of that out the last time I made a run at this windmill. John used an FPGA
development board with an 18 channel A/D, which also controlled modified firmware on the
motor driver
and digitizes the tach pulse to get actual tape speed.
Unfortunately, he never sent me the FPGA code, so I have to come up with my own digitizer
and figure
out how to drive the transport. Fortunately, it's a 9914V (vertical mount), so it
isn't auto-loading.
I did get a tape to move to loadpoint from the front panel, so the mods might not be too
bad. He did
send me a disassembly of the microcontroller code with the patches he made.
Reading this presentation, I think he switched to 3490 36 track heads at some point.
http://storageconference.us/2008/presentations/3.Wednesday/5.Bordynuik.pdf
MANY years ago, I bought a dozen 3480s in Chicago and stripped them for the heads at my
parent's
farm in Wisconsin, so I could try grafting one onto another transport if I had to.
I've been unsuccessfully
trying for years to get the schematics for a 9914 or 9914V (they aren't inlcuded in
the service manual).
On 8/12/16 12:29 AM, emanuel stiebler wrote:
On 2016-08-11 20:36, Al Kossow wrote:
One of the highest projects I have in the queue
is getting one of John's
M4 9914V drives with 18 track MR heads running in my new lab at CHM.
What's the interface on the 18 track head?