Tandy 1000 SL Technical Reference Manual page 444

3-4-9. Check of Asymmetry
Adjustment i s applied only f o r a model with v a r i a b l e r e s i s t o r on the
PCBA
M F D control.
( A )
Equipment
(1) Common screwdriver, small s i z e
( 2 ) Work disk
( 3 ) SKA o r u s e r ' s system
( 4 )
Oscilloscope ( n o t required when SKA3 i s used)
(B-1) Check and adjustment procedure (General method)
(1) Connect an oscilloscope t o the READ
DATA
i n t e r f a c e l i n e .
Oscilloscope range: DC mode, 2V, 0.5
? ,
l p s e c
( 2 ) I n s t a l l a work disk and s t a r t the spindle motor.
(3) S e t t h e head t o t h e innermost t r a c k .
(4) Execute t h e head loading.
(5) Execute 1F write operation f o r one r o t a t i o n of t h e disk (125KHz of
WRITE
DATA
frequency f o r FD-55BR/FR and 250KHz f o r F D 5 5 G R ) .
(6) Measure the asymnetry r e f e r r i n g t o Fig.3414.
Note: Oscilloscope should be so s e t t h a t t h r e e
READ DATA
pulses can be
observed. Asymmetry value s h a l l be measured a t t h e second READ
DATA
pulse from the t r i g g e r pulse.
( 7 ) Confirm that t h e average asymmetry i s within t h e following range.
-
3432
-