Kistler-Morse KM LD360s - Manual (Page 27)

Small Amplitude
Changes or Erratic
Fluctuations in display
readings Fluctuations can be caused
by moisture in cable conduit,
junction boxes, or PCBs. Check conduit, junction boxes, and PCBs for
water contamination. Find water entry source
and correct problem. Dry with a hair drier.
Remove/replace corroded parts and materials.
CAUTION
If using sealant to eliminate water entry, use
Sikaflex ™ 1A polyurethane sealant or Dow
Corning™ RTV 739 or RTV 738. Other
sealants may contain acetic acid, which is
harmful to electronics.
Fluctuations can be caused
by damaged Load Disc. Using Digital Multimeter (DMM), check
resistance for individual Load Discs:
1. Set meter resistance scale to accommo-
date measured range up to 20,000 ohms.
2. Remove one Load Disc’s wires from
junction box terminal.
3. Put one DMM lead on Load Disc’s white
wire and other lead on brown wire.
Record resistance reading, and verify it is
8,750 ± 250 ohms and stable. If reading is
outside this range, Load Disc is damaged
and must be replaced.
4. Put one DMM lead on Load Disc’s white
wire and other lead on black wire. Record
resistance reading, and verify it is 8,750 ±
250 ohms and stable. If reading is outside
this range, Load Disc is damaged and
must be replaced.
5. Verify readings from Steps 3 and 4 are
within 400 ohms of each other. If not,
Load Disc is damaged and must
be replaced.
6. Repeat Steps 2 through 5 for each suspect
Load Disc, until damaged Load Disc is
located.
Problem Problem Details Solution
Appendix C: Troubleshooting the Load Disc System
C-2