Fault Isolation Tests; Table 8-3 Coarse-Zero Jumper Pattern - Honeywell 7866 Operation And Maintenance Manual

MSB LSB
10 001010
11 001011
12 001100
13 001101
14 001110
15 001111
Step
If current is
above 450 µA
1
below 250 µA
above 450 µA
2
below 250 µA
above 450 µA
3
below 250 µA
above 450 µA
4
below 250 µA
above 450 µA
5
below 250 µA

8.2.3 Fault Isolation Tests

The troubleshooting guide provided in Table 8-4 can be used in conjunction with the fault-isolation tests to
identify and solve most analyzer problems. If the source of trouble is not apparent from the symptoms
given in the table, then the following checks may be used to isolate the site of an unknown source of
trouble to either the sensing unit or the 7866 Digital Controller. The troubleshooting table can be used to
better identify the malfunction, either before or after these isolation tests are performed, according to the
specific symptom. When the fault is thus generally located, replace the faulty circuit card with a spare and
return the card to Honeywell for repair in order to quickly restore service.
The following is a list of test equipment required to perform all of the various tests and troubleshooting
procedures described in this section:
•
Simpson Model 260 Multimeter or equivalent 20,000 ohms-per-volt meter for voltage, current, and
resistance measurements.
Resistor 2500 ohms ± 5 %
•
•
Resistor 30 ohms, 25 watts
•
Six-volt battery
•
Adjustable resistor (up to 20 K ohms)
•
Span gas mixture equal to full-scale reading
9/06 7866 Triple Range Digital H
MSB LSB
26 011010
27 011011
28 011100
29 011101
30 011110
31 011111

Table 8-3 Coarse-Zero Jumper Pattern

G Y
1 0
0 1
1 1
X 0
X 1
X X
X X
X X
X X
X X
X X
and CO Analyzer/Indicator - Operation and Maintenance
2 2
MSB LSB
42 101010
43 101011
44 101100
45 101101
46 101110
47 101111
Jumper Positions
O R
0 0
0 0
0 0
1 0
1 0
0 1
1 1
X 0
X 1
X X
X X
Troubleshooting
MSB LSB
58 111010
59 111011
60 111100
61 111101
62 111110
63 111111
N K
0 0
0 0
0 0
0 0
0 0
0 0
0 0
1 0
1 0
0 1
1 1
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