Agilent Technologies E1343A Service Manual page 26

Test 2-1: Closed Channel Resistance Test
Measuring Protection
Resistors
NOTE
Resistor
R20
R21
R22
R23
R24
R25
24 Verification Tests
This test verifies that all relay contacts meet the closed-channel resistance
specification for the multiplexer. If the closed-channel resistance of any
relay contact is greater than 2Ω, the relay should be replaced. This test uses
the test fixture (see Figure 2-1).
Since there are 100Ω protection resistors (R20 through R31) in the relay
paths, measure the protection resistor values to begin this test. The values of
the protection resistors are then subtracted from the measured path
resistance to determine the relay contact resistance. To measure the
protection resistor values, set the 3458A DMM to 4-wire ohms, autorange
and measure each resistor value with the DMM (see Figure 2-2). Record the
measured values in Table 2-1.
On the E1343A and E1344A, Resistors R22, R25, R28, and R31 are 1.0kΩ
resistors.
Figure 2-2. Typical Resistance Measurement Connections
Table 2-1. Measured Protection Resistor Values
Measured Value (Ω)
___________________
___________________
___________________
___________________
___________________
___________________
Resistor
Measured Value (Ω)
R26 ___________________
R27 ___________________
R28 ___________________
R29 ___________________
R30 ___________________
R31 ___________________
Chapter 2