Tandy 1400LT Service Manual page 125

@ Internal FDD Troubleshooting
I s Boot s e l e c t s w i t c h
Has t h e l o c a t e d d i s k e t t e
b e e n p r o p e r l y i n i t i a l i z e d ?
I
C h e c k
t h e c o n n e c t o r s a n d
c a b l e c o n n e c t e d t o t h e FDD.
Check t h e power s u p p l y
of FDD ( t 5 V )
Check "FD POWER CON" s i g n a l .
T R 1 6 : B a s e
Th e l e v e l of "RESET765" s i g n a l
when FDC
i s
t u r n e d o n
P i n 5 3 of GATE5 s h o u l d b e low l e v e l .
c 3
Check t h e f r e q u e n c y
a t P i n 3 o f IC57.
I t m u s t b e 4MHz.
of GATE3
a n d TR16
T R 1 7 : Base
Check L3,
C 6 2, R 5 3 a n d
C63
5-16