Yaesu FT-901DM Maintenance Service Manual page 84

10. APF SELECTIVITY
The selectivity of the APF (Audio Peak Filter)
can be adjusted by varying VR¢o,, located on
PB-1705. Clockwise rotation of VRso; will yield
sharper selectivity of the filter.
AF unit (PB-1705)
11. KEYER ADJUSTMENT
VR32702 controls the dot-to-spa ratio for the
built-in electronic keyer: this is normally set to
1:1 at the factory. VR279; adjusts the symmetry
between dots and dashes. Once VR479; 1s set.
this setting is correct for all keying speeds. Ad-
justment of VRo2792 will make both dots and
uniformly with respect to the
dashes chan,
space. Both of these controls are located on
PB-1728.
Keyer unit (PB-1728)
SERVICING
12. CLARIFIER ADJUSTMENT
With the transceiver in the receive mode, push
the RX CLARIFIER button and set the CLARI-
FIER control to 0. Tune in the marker signal on
any band and then switch the RX CLARIFIER
button OFF. If the frequency changes at all,
adjust potentiometer VR219;. which is located
inside the cabinet near the CLARIFIER control
potentiometer.
MJI200 ——_=———~,
(VCO unit)
Tune board
(PB-1720)
VRoi0; Band switch
13. VOLTAGE REGULATOR ADJUSTMENT
Connect a VTVM DC probe between pin 10 of
MJ, (PB-1717) and ground. Adjust 6V SET
potentiometer VRj,s9; for exactly 6 Volts as
indicated on the VTVM.
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