HP 437B - POWER SENSOR DETECTION CIRCUITRY TROUBLESHOOTING (continued)

HP 437B
Service Sheet BD1
2.
Refer
to
Figure
8-10,
A4TP18.
Examine
the
displayed
waveform
at
point
B
(if
the
power
sensor
is
connected
to
the
front
input
port)
or
at
point
C
(if
the
power
sensor
is
connected
to
the
rear
input
port),
The labels on Figure 8-10 indicate measurements by the ADC input
multiplexer as follows:
A: Measures the ground connection at B-GND.
B: Measures the voltage level at the front sensor.
C: Measures the voltage level at the rear sensor.
D: Measures the output of the low-pass filters.
3.
Using
the
table
below,
verify
the
proper
voltage
at
A4TP18
points
B
or
C
for
the
power
sensor
you
are
using.
Table 8-7. Sensor Power Ranges, Resistor Values, and Voltages
Power Sensor
Power
Sensor
Power
Range
Resistor
Value
A4TP18
Voltage
8484A -70 to -20 dBm
(100 pW to 10 pW)
8481A, 8482A,
8483A, 8485A,
R8486A, Q8486A,
Range Calibrator -30 to +20 dBm
1 upW to 100 mW 02 (Gnd)
8481H, 8482H -10 to +35 dBm
100 upW to 3 W 346 ka
8481B, 8482B 0 to +44 dBm
1 mW to 25 W 6.19 ka
SERVICE 8-39