On 8/12/16 10:14 AM, emanuel stiebler wrote: > On 2016-08-12 10:27, Al Kossow wrote: >> 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 > OK, >> 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. > > 18/36 channels? Which sample rate? Resolution? >
had to dig up my notes from 2013 the drive I have is 18 track (3480 head) with 18 NE5592D differential amps the A/D is a AD7322 2 channel 12 bit 1msample I have no idea what the actual sample rate used is and I can't really tell from the picture in the presentation >> 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). > > So, going for the 36 track heads too? I would be happy just to get this one running. I'm not too keen on digging for more head stacks right now.
