HP 85027A/B/C Service
8.
Turn the bridge over. Remove the four screws which fasten the microcircuit
assembly. Take out the microcircuit assembly. Note the stainless steel spacer
under it.
9.
Install the spacer over the screw holes and the bridge microcircuit assembly over
the spacer. Reinstall the four microcircuit assembly screws.
10.
Perform in reverse sequence steps 2 through 8.
11.
Refer to Section 5, Adjustments, and perform them as required to match the
microcircuit to the preamplifier and pass the performance tests.
12.
Attach the new label to the bridge housing.
Power Supply Check
1.
Connect the power cord of the bridge (Wi) to the analyzer and turn on the
analyzer.
2.
Refer to Figure 8-i and check the power supply voltages of +15, -12.6, +8 and -5
volts at the 4 pads indicated. Since the +1SV and -12.6V are supplied by the
analyzer, those voltages are specified in the analyzer’s manual. The +8V should be
+8.3±0.3V;-5V should be -5±0.2V.
5V
Figure 8-1. A 2 Circuit Board Power Supply Check Points
3.
Refer to Figure 8-1 and check the power supplies at the various components as
indicated by malfunction.
8-5