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No pulse
output; wrong
pulse period
Set thumbwheel
switches to
"0000", check
waveform at T P 1 .
Use both sweep
—
r a t e s as indie, in
Q & 0
Note
pulse period of flg
NO
SIGNAL
Trigger scope
from neg slope
of pulse at T P 1 .
■ Check signal at
Q1(C). Check 10
input pulses a r e
blocked by g a l e . f l
More or l e s s
■ than 10 pulses -
blocked by gate
Adjust value of
Within C14 so exactly
_
Check signal a t
±
j / j s e c l " pulses a r e
•Q13(C). N o t e — — — |
blocked by gate
pulse width
as. 5 jisec
O
l _ Check Q16 &
a s s o c . circuitry
_Will not _
adjust
— Gate working •
Check preset
signal at T e r m .
C of S1(A,
& D); should]
neg pulse approx
. 5 )j.sec width
& > 3V ampl.
r
NO
K, B, C,
I
ould be
°
a
" " ' " "
v
YES
L
Check signal at
IC8(10): should
be pos. pulse
approx. . 5
,usec width &
1. 5V amplitude
Check preset
coupling diodes
(CR3-6. 10-13, '
15-18 & 21-24)
r
NO
Check dc voltage
at IC8(6); check -
R29& C10
I
Check preset
YES d r i v e r s &
I— assoc. circuitry
(Q5,Q10,Q15)
Check thumbwheel
switch (see table)
■ Gate not working ■
Check signal _
at 0 . 1 3 ( 0 ^ ^
O
, _ Check Q13,Q14,Q16
NO & a s s o c . circuitry
YES_ Check Q2,Q3 &
a s s o c . circuitry
Check dc voltage
— at Q3(C); should
be < .5Vdc
NO
H
YES
L
Ground Q3(C) &
Q7(C); Check
-
signal at IC10(1)
Check signal
|~~ at Q 4 ( C ) 0 '
NO
Go to part "A", Table 5-7
O O R
WRONG
PULSE
PERIOD
Check signal at
IC4(2); should be
' pos pulse approx
1.25V, 1.5 fjsec.
■ I n c o r r e c t •
YES
Check signal
I
at IC9(6)g%
NO
"
Check signal
a t Q l l ( C ) ^ |
I
^
YES
Check signal
atQ8(C)
Q
Troubleshoot
■ Reset line
(C6,Q7,IC11)
NO
Replace IC11
Replace IC8
THUMBWHEEL SWITCH
CHECK TABLE
Check signal continuity thru thumb
wheel switches SI (A, B, C, D) by s e t
ting switch to each number and ob
serving waveform at output line (see
table).
Should be g r e a t e r than 3V
negative pulse approximately 0.5 jusec
in amplitude. If "ok" check continuity
between switch output and IC decade.
Number
1
2
3
4
5
Output
on Lines
1
2
1,2
4
1,4
Number
6
7
8
9
0
Output
on Lines
4,2
4 , 2 , 1
8
8,1
None
Check dc voltage
at IC9(4,8); Check
"CR25 & continuity-
between IC9(3, 5)
1
& IC10(6,1).
YES
L_ Check Q l l , CR25
& a s s o c . circuitry
■ Go to part " B " , Table 5-7
• Replace IC9
O S
^ ' O
O
Q.
C
CD
CJI
01
CQ
0)
3
CD
O
0)
3
Q .
C O
3 '
r-t-
CD
3
ID
3
O
CD
o>
CD
I
en
O
c
CD
Cfl
3 "
o
o
•-*
3 '
CQ
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