154 Power Amplifier Fault Finding TB8100 Service Manual
© Tait Electronics Limited September 2006
Table 8.1 Test point voltages on the control board
Test
Point Pin Pin Name
Tx Off
Voltage
Tx On
Voltage
a
Notes
SK101 1 & 4 GND ground
2 & 3 +28V-FILT-CONTROL 26V to 30V 26V to 30V filtered supply
SK102 1 POWER-CONTROL <0.5V 1.5V to 6V analogue voltage
2 RF-DET >6.0V <0.8V RF drive present, +11dBm
3 PA-KEY-COAX >4.0V <0.5V logic level
4 DRIVER-TEMP digital digital digital signal, 0V and 5V
SK103 1 STANDBY <0.5V <0.5V logic level
2 DRIVER-CURRENT-MICRO <0.05V >0.5V <1.1V current =
measured voltage ÷ 2
3 DRIVER-BIAS-MICRO <0.05V 3.37V typical analogue voltage
4 +10V-SWITCHED 0.05V 10V 10V regulated supply to
6W board
SK104
SK105
SK106
SK107
1 FINALX
-CURRENT-
MICRO
b
<0.05V 2V typical current =
measured voltage × 2
2 FINALX-BIAS-MICRO
b
<0.05V 4V typical typical analogue voltage
3 FINALX-TEMP
b
digital digital digital signal, 0V and 5V
4 GND signal ground
SK108 1 FWD-PWR-DC 0.27V 2.5V Analogue, proportional to
forward power
2 REV-PWR-DC 0.27V <0.6V Analogue, proportional to
reverse power
3 +10V-LPF 10V 10V 10V regulated
4 GND ground
TP100 +5V-DIG 5V 5V regulated supply
TP102 +10V 10V 10V regulated supply
TP103 –3V –3V –3V regulated supply
TP204 POWER-LEVEL <0.05V >0V <4.5V analogue, will vary with set
power
TP206 scaled voltage supply 1.96V typical 1.96V typical analogue, 1.5V to 2.45V
TP211 KEY-CONT <0.05V >4V digital
a. Measured when the PA is set to its rated RF output power (i.e. 5W, 50W, or 100W according to model).
b. X = final 1 or final 2.
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