30 Oct
2005
30 Oct
'05
2:11 p.m.
What I would do
(and alas it needs a 'scope would be to remove the R/W
chip and connect the differential inputs of the 'scope to HC and H0
(say). Run a recorded, but unimportant 'scratch tape' through the thing
and see what signal you get. Then design a differential amplifier to
bring it up to the sound card input levels.
The preamp schematic from the 9815/9825 tape drive might be a start. Does
anybody know if those drives are tape and track compatible with the 85
drive?
They DO use the same tape so they must be compatible. I don't know about the track spacing but I would think they would be the
same. It should be
easy enough to check with some MagnaSee. I THINK that's the name of the
liquid that you put on mag tapes/cards to see the magnetic tracks. I have a
can of it around here somewhere but no idea where it's at at the moment.
I am still looking for a can of that stuff.
Could you not
design your own motor controller? It's 'just' a matter of
controlling the motor voltage to get the right frequency output from the
tacho sensor.
It's a servo loop so I don't think it would be that easy. You'd have to
have the correct response times and all that to make it work properly. And
remember that these motors have both a high spped and normal reading speed
as well as reverse so your controller would to be capable of handling all