Fluke 2180A - Manual (Page 78)

21X0A-006
Table 606-2. Limits Option Troubleshooting (cont)
STEP
NO.
ACTION
Go to the step
number given
for correct
response
YES NO
17 Does the signal at U11 -3, U9-3, and U7-3 toggle? 19 18
18 Check U11, U9, and U7. Repair as required then resume at Step 1.
19 Does the DATA line toggle? 21 20
20 Check Q1, Q2, U3, U5-10 and their associated components. Repair as required then resume at Step 1.
21 Are the clock and data signals present at pins 11 and 9 of U6, respectively? 23 22
22 Check U5 for the clock, repair as required then resume at Step 1.
23 Is the collector of Q9 low? 25 24
24 Check Q9, Q3, U6-12 and their associated components. Repair as required then resume at Step 1.
25 Check the indicator CR1 and the relay on the Main PCB. Repair as required then resume at Step 1.
26 Set the FUNCTION switch to greater than (>) and input a temperature from the thermocouple that exceeds
the preset limit.
27 Does the LIMIT indicator illuminate and the relay contacts close? 29 28
28 Check for a Function BCD code of 1 (001 ) at pins 4, 5, and 6 of U7. The sign at U7-7 is high for plus and low
for minus. Check that the thumbwheel switches reflect the BCD codes set on them. Repair as required then
resume at Step 1.
29 Set the FUNCTION switch to the Delta (^) position and set the thumbwheels to the desired base.
30 Is the difference between the thermocouple Input and the preset base displayed? 32 31
31 Check for a Function of BCD code of 2 (010) at pins 4, 5, and 6 of U7. Check that the thumbwheel switches
reflect the BCD codes set on them. Repair as required then resume at Step 29.
32 Set the FUNCTION switch to the minimum ( Ì ) position and depress the INITIALIZE MIN/MAX switch. i n
33 Does the thermometer display reflect the lowest temperature input from the thermocouple since the switch
was depressed? 35 34
34 Check for a Function BCD code of 3 (011 ) at pins 4, 5, and 6 of U7. Check U2-4 and 5, U4-3 and 4, U6-1, the
initialize switch S7 and their associated components. Repair as required then resume at Step 32.
35 Set the FUNCTION switch to the MAXIMUM ( J ) position and depress the INITIALIZE MIN/MAX switch.
36 Does the thermometer display reflect the highest temperature Input from the thermocouple since the switch
was depressed? 38 37
37 Check for a Function BCD code of 4 (100) at pins 4, 5, and 6 of U7. Repair as required then resume at Step 35.
38 Troubleshooting of the 21XO-006 Limits Option is complete.
606-4