Heathkit HW-12 - Troubleshooting

ear ener Snes
TROUBLESHOOTING CHART
|
TRANSMITTER
DIFFICULTIES
|
POSSIBLE
CAUSE
|
CARRIER
NULL
control
changes
1,
FUNCTION
switch
in
TUNE
position,
in-
carrier
ievei,
but
not
to
a
low
enough
serting
carrier,
level,
2,
Crystal
diodes
CR1
through
CR4
installed
|
backwards
or
are
faulty,
|
|
3.
Transformer
T1
incorrectly
aligned,
| No relative power indication.
Resistor R61 burned out, due to trans-
mitting without antenna,
| 2. Antenna shorted,
3
nea ov ers
TUNE LEVEL set too iow,
Chopped
or
broken
modulation,
1,
MIC
GAIN
control
set
too
high,
especially
on
peaks,
|
2.
Faulty
microphone
cable
or
connections,
3.
Receiver
cutoff
bias
line
partially
shorted,
|
Check
voltages
and
resistances,
|
|
Radical
change
in
BIAS
SET
reading,
|
1.
Changed
power
supplies
without
Pechecking
|
tranamittar
adduatm
ant
Uh AAAS ALLU LL AMY usTMeEnNtT,
|
Plates
of
RF
final
amplifier
tubes
get
|
1.
No
bias
on
tubes,
Check
voltage
and
re-
|
red
hot,
sistances,
Very
low
input
to
grids
of
RF
final
Bey
Coile
2h?)
cand:
-improperly.
installed.
amplifier
tubes
from
driver
V5,
|
Check
color
dot
markings.
2,
T2
not
aligned
properly
Receiver squeals and oscillates 1,
| with no antenna connected, |
Received signals cannot be tuned . Other station operating on other sideband
in
properly,
Try
other
portions
of
the
dial,
No
sound
from
speaker,
1,
Speaker
unplugged
or
faulty.
2.
Unit
is
transmitting
,
oe ‘ “ ga