Yaesu FT-901DM Maintenance Service Manual page 70

COUNTER UNIT CAPACITOR REVERSAL
In FT-901DM units bearing serial numbers
8F030001 through 8H059999, the markings on
PB-1729 showed the polarity of C294 incorrectly.
As a result, the capacitor was installed correctly
according to the marking, but incorrectly accord-
ing to the intended purpose.
Modification Procedure:
(1) Remove the COUNTER UNIT, PB-1729,
from the transceiver. Locate C29s4, and
observe the polarity. On sets bearing the
above serial numbers, if the capacitor is in-
stalled with reversed polarity according to
the circuit board making, your unit is already
modified. If it is the same as the circuit board
marking, remove and discard the capacitor.
A correctly installed capacitor has its mark-
ings facing in the direction of Q2903.
BEFORE
Capacitor installed per PB marking
(incorrect).
Remove and reverse C2954.
T2902
T2931 2
SERVICING
(2) Install a new C2954 (1 pF, 35 WV, tantalum)
as shown in the drawing below. Its markings
should face Q2903.
(3) Replace the COUNTER UNIT. Modification
is now complete.
- I+
Markings should face Q2003.
Capacitor reversed according to PB
marking.
C2954 with correct
1
iB polarity.
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