HP 436A Operating And Service Manual page 74

Model 436A
Adjustments
ADJUSTMENTS
5-20. A-D CONVERTER AND LINEAR METER ADJUSTMENT
REFERENCE:
DESCRIPTION:
Service Sheets 7 and 8.
The A-D converter circuit is adjusted to obtain the specified digital readout accuracy
and the meter circuit is adjusted for a corresponding indication.
RANGE
CALIBRATOR
POWER METER
DIGITAL VOLTMETER
EQUIPMENT:
PROCEDURE:
iRECOROE;i
0 0 0 0
cw
~
L OUTPUT _J
:~Io
Cl
POWER METER
SENSOR
.._
-
-
-
Figure 5-5. A-D Converter and Linear Meter Adjustment Setup
Range Calibrator . . . .
Digital Voltmeter (DVM) .
HP 11683A
HP 3456A
1.
Set the Power Meter switches as follows:
CAL FACTOR
% .
POWERREF .
MODE . . . .
RANGE HOLD
LINE . . .
100
off (out)
WATT
off (out)
ON (in)
2. Set the Range Calibrator switches as follows:
FUNCTION.
RANGE . .
POLARITY.
LINE . . .
STANDBY
lmW
NORMAL
ON (in)
3. Connect the equipment as shown in Figure 5-5.
4. Remove the Power Meter top cover and set the DVM to the 1000 mV range.
5. Press the Power Meter SENSOR ZERO switch and wait for the display readout to
stabilize. Then release the SENSOR ZERO switch and wait for ZERO led to go
out before proceeding to the next step.
6.
Set the Range Calibrator FUNCTION switch to CALIBRATE and adjust the
Power Meter front-panel CAL ADJ control to obtain a 1.000 Vdc indication on
the DVM.
7. Adjust the Power Meter LIN potentiometer A3R37 so that the digital readout in-
dicates 1.000 mW.
5-7