F U N C T I O N Of Variable Resistors - Tandy 1000 SL Technical Reference Manual

Function of Variable Resistor
This item is applied only for a model with variable resistor on the
PCBA MFD control.
The variable resistor is correctly adjusted before the shipment of the
FDD and fundamentally it shall not be readjusted except for by a trained
technician.
R1 (for asymmetry adjustment)
Variable resistor for adjusting the asymmetry of the read data pulse.
Write and read 1F data and observe the pulse intervals at the READ DATA
output line. Then adjust the variable resistor so that the read data
asymmetry takes the minimum value in Fig.220. Repeat each adjustment
alternately for side 0 and side 1 heads to obtain the minimum asymmetry
for both sides. Refer to item 3-4-9.
READ DATA
1F interval
1
2
3
Asymmetry at adjustment
B,F models: O.Gps,Max.
G
model: 0.3~s,Max.
Trigger
Note: When the READ DATA waveform is observed at the DOUT terminal
of the
SKA,
positive going pulse is observed.
(Fig.220) Read data asymmetry
-
253
-