16 Jun
2015
16 Jun
'15
11:20 a.m.
On 06/16/2015 11:08 AM, Henk Gooijen wrote:
The round (approx 2" diameter)
"bearings" of the TU80 do not rotate.
Instead, the metal has tiny holes. Air pressure pushes the tape away
from the bearings. As the tape moves, due to movement pressure, the
tape comes closer to the air bearing. That is measured. To get the
air pressure back to some sort of equilibrium the pickup or supply
reel speed is adjusted.
That is how I understand the mechanism ... now writing this down, I
think I should read up the Theory of Operation chapter ...
Pretty much the standard CDC vacuum-column design since the 1960s. The
TU80 is, after all, a CDC product. Two counter-rotating capstans--tape
movement is determined by applying positive or negative pressure to
ether or both (i.e. positive pressure on both results in the tape "floating"
--Chuck