HFOPremixer Circuit Board
TROUBLESHOOTING CHART
Refer to the "X-Ray View" and "Voltage Chart" (fold-out
from this page).
L
SYMPTOM
HFO will not oscillate or
output voltage very low
(all bands).
HFO inoperative, one band
only.
I
Premix output low, all bands
(HFO
is
OK).
POSSIBLE CAUSE
1.
Bandswitch wiring.
2.
I
lV missing.
3.
Q405.
1.
BAND switch.
2.
For the band concerned, the
associated crystal, transistor.
switching diodes, coil.
1.
VFO signal low or missing.
2.
0406, 0407.
Premix output low, one band
(HFO is OK).
Premix output low.
10
meters.
(HFO
is
OK).
t
1.
BAND switch.
2.
Filter components associated
with the band.
VFO filter board components.
.
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