Ten-Tec 243 - Page 10

9-243
-9-
80505 AMP/SWITCH
The voltage applied to pin A, B, or C determines whether buffer amplifier
Q3 amplifies the @MNI PTO, the Model 243 PTO or the XTAL oscillator. DI through
D3 are PIN diodes which are forward biased when the associated control line is
set high. If A or B is high, Ql or Q2 respectively is also turned on, allowing
the signal to pass to Q3.
Pin Voltage Readings - (20 meter band. SB. REMOTE in VFO position. MODE
switch in position 3.)
Pin Transmit | Receive Pin Transmit | Receive
(REMOTE switch on X-1 position. MODE switch on position 3.)
Transmit | Receive
Semiconductor Voltage Readings - (REMOTE switch on VFO position. MODE switch on
position 3.)
Transistor Collector Base Emitter
Transmit | Receive Transmit | Receive Transmit | Receive
91 7.6 13.8 3.5 0
92 13.8 7.6 0 3.6
93 5.5 5.5 2.9 2.9
B
To
Q1,2,3 D1,2
Semiconductor pins
viewed from top of
PC board