Single Gas Instrument Service Manual
Page 14
Bacharach, Inc.
Instruction
0019-9166
4.0 TROUBLESHOOTING
CHART
Symptom
Cause
Remedy
Batteries dead
Batteries installed backwards
P.C.B. defective
Backlight or its switch is defec-
tive
Sensor connections loose or
broken
Sensor Membrane blocked with
water or dirt
Sensor depleted or defective
P.C.B. defective
LCD loose or defective
P.C.B. defective
Replace batteries with four
fresh “C” Alkaline cells.
Insert batteries correctly.
Wait at least one minute be-
fore switching on unit to allow
its PTC resistor to cool.
Replace P.C.B. Refer to
Section “2.5 Printed Circuit
Board Replacement.”
Replace P.C.B. Refer to
Section “2.5 Printed Circuit
Board Replacement.”
Check Sensor connections
(Fig. 2-2).
Remove Sensor and replace
its Membrane. See Fig. 2-2.
Replace Sensor. Refer to
Section “2.4 Sensor Replace-
ment.”
Replace P.C.B. Refer to
Section “2.5 Printed Circuit
Board Replacement.”
Carefully re-seat LCD in its
socket. If segments are still
missing, replace LCD.
Replace P.C.B. Refer to
Section “2.5 Printed Circuit
Board Replacement.”
No display when unit is
switched on
Backlight won't light
Unit doesn't respond to gas
(e.g., from calibration gas)
LCD segments missing
