Troubleshooting - HP 85020 A Operating And Service Manual

Model 85020A/B
Service
SECTION VIII
SERVICE
8-1. INTRODUCTION
8-2. This section provides instructions for troubleshootina and
repair of the 85020A/B Directional Bridqe.
8-3. CAUTION NOTES
8-4. The CAUTION sign denotes a hazard to the instrument. It
calls attention to an operating, maintenance, or repair procedure
which, if not correctly performed or adhered to, could result in
damage to or destruction of part or all of the instrument. Do not
proceed beyond a CAUTION sign until the indicated conditions are
fully understood and met.
8-5. THEORY OF OPERATION
8-6. The operation of the 85020A/B is described to assist with
troubleshooting procedures. Schematic diagrams are supplied for
the A1 directional bridqe circuit and the A2 preamplifier,
together with a component locations diagram for the A2
preamplifier assembly.
8-7. TROUBLESHOOTING
8-8. Troubleshooting the 85020A/B involves performing the
Operator's Check and the Performance Tests. If a problem persists,
refer to TROUBLESHOOTING PROCEDURES later in this section. The
troubleshooting procedures are designed to help the technician
isolate a problem to the defective component. A troubleshooting
flow diagram is provided in Figure 8-4.
8-9. RECOMMENDED TEST EQUIPMENT
8-10. Equipment recommended to test and maintain the instrument
is listed in Section I, General Information. If the equipment
listed is not available, equipment that meets the critical
specifications listed may be substituted.
8-1