IEC 30 Series - Page 50

SECTION 5
Table 5-1. Troubleshooting Guide (Continued)
Remarks
Possible Cause
Symptom/Step
1.
Q3 open.
and short TP17 to
ground for test.
b.
Set FREQ dial @ 3.0
2.
IC2
faulty.
Voltage @ CR9
cathode less nega- 3.
Voltage across R16 less than 5. 8v: Voltage at
See step 19.
tive than -330 mv. TP8 improper.
FREQ Control faulty.
Voltage @ CR4
cathode -5v.
19. FREQUENCY
CONTROL
a.
TP8 less negative
1.
Q59 open.
than TP9 when
FREQ Dial @ CW 2.
IC12
faulty.
Stop.
3.
R1
open or misadj usted.
4.
R5
misadjusted or tuning assembly out of
mechanical alignment.
Q50 open collector.
@ Top of FREQ DiaL
b.
Dial Linearity poor
20.
POWER SUPPLY
1.
Fuse blown.
a.
Entirely dead.
2.
Sl, S8 open.
1.
IC10 open.
b.
All
voltages too high.
2.
R145
open.
3. VR4, Q23,
Q24
shorted.
4. VR2 open.
c.
All
voltages too low. 1. VR2 shorted.
2. VR4 open.
d.
No
regulated voltages.
1. Q25 shorted.
2. Q23. Q24 open.
e.
No negative regu-
1. Q28.
Q29
open.
lated voltages.
2. Q30 short.
3. ICll open.
Q26.
Q27
short.
f. +5v too high.
g.
+5v too low.
Q26,
Q27 open.
h.
-5v too high. Q31,
Q32
shorted.
5-10