IET Labs, Inc. 1864-1644, User And Service Manual

Page: 32 / 46

SERVICE AND MAINTENANCE
1864-1644 Positive Polarity Megohmmeter
22
16. Set the POWER/OFF switch to OFF and
disconnect the decade resistor.
17. Connect the Digital Multimeter between the
GUARD and -UNKNOWN terminals
with two single banana plug patch
cords.
18. Connect the two ground terminals together
with a third patch cord (Figure 6.1).
The megohmmeter shorting link
should remain attached only to the
ground terminal.
19. Set the multiplier switch in the full ccw posi-
tion (1M, 100k) and the function switch
to MEASURE.
20. Measure the various standard resistors of the
megohmmeter with the DMM according
to the settings and tolerances of Table
6.2. Use the IET LOM-510A megohm-
meter for resistance values beyond the
range of the DMM.
Figure 6-1. Connections for measuring standard
resistors with a digital multimeter
+ -