Yaesu FT-901DM Maintenance Service Manual page 28

PART DESIGNATIONS ON CIRCUIT BOARDS
PLUG-IN MODULES
The FT-901DM_ utilizes computer-type plug-in
modules, for ease of servicing. Extender boards of
10 pins (single and double face), 18 pins (single
and double face), and 22 pins (single face) can be
had from your Yaesu dealer to provide access to
test points.
All parts used in the FT-901 transceivers have a
part number (e.g. Qsoe) assigned to them.
Part numbers 01-99 (e.g. Ry2) are located on the
main chassis. Other parts located on the printed
circuit boards are assigned a three or four digit part
number. The last two digits are the part number
for that board; the first one or two figures are the
code for the printed circuit board.
Thus, Q3o1 is transistor number 01, located on
circuit board #3, which is the FILTER unit. Refer
to the chart below for a tabulation of the code
numbers assigned to the various circuit boards used
in the FT-901 trnsceivers.
10 Pin
:
°
tt
CaoOIAnkwn
10
EXTENDER BOARDS
2-1
Unit
RF
NB
FILTER
IF
AF
VOX/MARK
CARRIER
VFO
FM
RECT A
PLL
Vvco
XTAL
RECT HIGH 8
CAPACITOR
DRIV
FINAL
RECT C
SELECT SW
sw
TUNE SW
LEDA
REJ SW
TRIMMER A
TRIMMER B
TRIMMER C
KEYER
MEMORY
COUNTER
DISPLAY
DIODE SW
DC-DC CONVERTER
TECHNICAL NOTES
Board designation
PB-1702
PB-1703
PB-1716
PB-1704
PB-1705
PB-1846
PB-1706
PB-1440
PB-1707
PB-1708
PB-1709
PB-1710
PB-1711
PB-1708
PB-1713
PB-1714
PB-1715
PB-1717
PB-1718
PB-1719
PB-1720
PB-1721
PB-1722
PB-1723
PB-1724
PB-1092
PB-1728
PB-1787
PB-1729
PB-1730
PB-1726
22 Pin