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Digital Clock_
not working
Check A5A3
(Q13,14, 15)
and circuits
No
I
Check signal
at A5A3(7)
_riJrL
15
°n
s
f = i p p
S
I
Yes
I
_ Check 1 P P S _
output
2V
- Y e s -
Troubleshoot clock movement
drive circuitry A16 (ICl,
" Q l l , 12).
Yes
- I n c o r r e c t -
Check sig. _
at A5A2(12)
o
No
.
Check sig.
at A5A2(1)~
ok
Check
h4.2V
Front Panel
No 1 PPS output
Check r e a r panel
1 PPS output
—-None •
Yes
Check, A16Q9
& associated
circuitry. Check
cabling.
not
moving
I
_Check Clock
second hand
moving
incorrect
at A5A2(9)
Check continuity
from A16A1J1.
Check A6 output.
Check 0-1 tisec
time delay at
A5A4(1). Should-
Troubleshoot
IC16, Q8,
Q10, Q12
I
No
Check p r e s e t
pulse at A5A3-
(Q8,10,12)
I O
Yes
Check
IC17A&B
Yes
Check r e s e t
pulse at A5A3
(Q7, 9,11)
I
No
Check gating
signal at
No
Troubleshoot
A5A3(Q7, 9,
11, ICl 5)
Troubleshoot
+ 4.2VonA5Al
I
No
A5A3IC17B(7)
O
Troubleshoot
A5A3(Q6,IC2C,D)
Yes
I
Yes
Check sig.
at
A5A3IC12A(6)
©
Check CR1 thru
16 & CR19 thru
26. Check p r e s e t
signal paths to
thumbwheel switch
for short.
No
Yes
Yes
I
Troubleshoot
1 MHz input ckts
A5A2(IC2, IC3)
&(IC4thruIC14).
Set thumb
wheel switches
to "000000"
—
and recheck
No
Troubleshoot
A5A3IC3 thru 8;
ICl, 2(A, B);amp.
Ql thru Q5.
No
Check signal at
A 5 A 3 I C 8 ( 1 ) ^
_
Check pulse output ckt.
- Y e s - A 1 6 (Q7 thru Q10) and
+ 13. 3V power supply
Yes
I
Check sig. from
NAND gates IC9,
10,11, p i n s 6 o r 7 .
o©
Q)
cr
CD
en
>
en
H
-i
o
c
CT
CD
CO
3 "
o
o
l-t.
■D
CD
Check A5A4 (ICl
& Ql).
Pulse
width controlled
by A5A4 (Cl, C2,
& ICl).
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