Heathkit H9 - Troubleshooting Charts

-
ry
TROUBLESHOOTING
CHARTS
POWER
SUPPLY PROBLEMS
CONDITION
POSSIBLE
CAUSE
1. Nothing happens
at turn
on.
1. Terminal not
plugged
in,
2. Fuse
F1 blown.
3. Primary/line
cord wiring.
4.
Switch 51 wiring.
5. Fuseholder wiring.
6. Power
transformer T1.
2.
Fuse blows.
1.
Check
primary
wiring.
2.
Short circuit on the
power
supply circuit
board.
3. Short circuit
across lransformer
secondary.
4.
Shorted rectifier
diodes. D101-D1 12.
5. Check for
shorts at the outputs
of the bridge rectifiers.
C1, C2,
and C105.
6.
Shorted
regulators.
1C101,|C102,
1Cl03.
7 .
Check
for
a short between
the collector of
Q101 and
the heat
sink.
8.
Incorrect
fuse.
9.
Power
transformer.
10.
Shorted regulator
outputs. P101-1
,
-2, -3, -4, -5, &
-1
'1
.
3. No s-volt output
or s-volt supply incorrect
(too
high
or
too
low).
1. |c101,lct02.
2. D101
-
D104.
3. C1.
4.
+s-volt
reference
$
(ground)
not
grounded
at P101-6.
4.
No
+12
volts,
or it measures too
high
ortoo
low.
1. lf
the
+26-volt
supply
is
below
+15
volts,
the
+12-volt
supply
will
also be
low.
2. lf the
26-volt supply is
OK, check 1C104 and the
+12-volt
reference
ground.
5. No
-
12 volts,
or it measures
too high
or too
low. t.
2.
3.
4.
5.
1c105.
R105 and
R106
interchanged
or wrong values.
D109
-
D1 12.
C107 installed
backward.
-
12-volt
reference
ground
not
grounded
at P101-6.
6. No
+26
volts,
or it measures
too high
or too low. 1.
tc103.
2. R103
and R104 interchanged
or wrong value.
3.
Q101, Q102.
4.
D105 - D108.
5.
+26-volt
reference
ground
not
grounded
at P101-12.
7.
No
+36
volts,
or
it
measures
too high
or
too low.
't.
c2.
2.
D105
-
D108.
3.
Transformer
T1.
8.
No
anode voltage when
other voltages
are OK.
CAUTION: Measure the
high voltage only with an
approved
high voltage
probe..
1.
Flyback transformer T2.
2.
Q1, Q307.
3. 1c301.
4.
L301, deflection
yoke.
5.
Shoried
foil
on the video
circuit board.