Carrier 48DK024 Controls Operation And Troubleshooting page 27

Fig. 34 — Relay Board Pin Terminal Connector (J9)
Table 13 — Voltage Reading
QUICK TEST
STEP NO.
1 2 3 4 5
1.-2.3. 0 0 0 0
2.4. 0 0 0 0
2.5. 0 0 0 0
2.6. 0 0 0 0
2.7. 0 0 0 0
2.8. 0 0 0 0
2.9. 12 0 0 0
3.0. 0 12 0 0
3.1. 0 0 12 0
3.2. 0 0 0 0 12
3.3. 0 0 0 0
NOTES:
1. Pins shown in boldface type will only be energized for 10 sec-
onds. All other pins will be energized continuously while at the proper
quick test step. The control will only stand in the quick test routine
for 10 minutes unless the display button is pressed.
2. Acceptable range for the voltage reading:
0 v — 0 to 4 v
12 v — 11 to 13 v
3. If any of these voltages are not measured, replace the processor
board.
Step 6 — Display board connection checkout.
1. Turn power to OFF position.
2. Disconnect the ribbon cable.
3. Connect negative lead of meter to TP18.
4. Turn power to ON position and go into quick test mode.
5. Place the other lead on terminals shown in table below,
and check voltage at pin terminals on pin terminal con-
nector J10 (see Fig. 35 for pin terminal connector J10
details):
PIN TERMINAL
17
18
20*
22*
24
*Voltage reading is dependent on the meter's impedance. Readings
may vary with different meters.
6. If voltage is not correct, replace processor board.
J9 PIN NUMBERS
6 7 8 9 10 11 12 13
0 0 0 0 0 0 0 0 12
0 0 12 0 0 0 0 0 12
0 0 0 12 0 0 0 0 12
0 0 0 12 0 12 0 0 12
0 0 0 12 0 0 12 0 12
0 0 0 12 0 0 0 12 12
0 0 0 12 0 0 0 0 12
0 0 0 12 0 0 0 0 12
0 0 0 12 0 0 0 0 12
0 0 12 0 0 0 0 12
0 12 0 12 0 0 0 0 12
VOLTAGE (DC)
5
5
2.5
2.5
5
Fig. 35 — Display Board Pin Terminal Connector (J10)
Step 7 — Potentiometer connection checkout.
1. Turn power to OFF position.
2. Remove plug connection from pin terminal strip J3.
3. Connect negative meter lead to terminal 2 of J3.
4. Turn switch to ON position and go into quick test mode.
5. Place the other lead on terminals shown in table below,
and check voltage at pin terminals on terminal connector
J3:
PIN TERMINAL
1*
3
6
8*
10*
12
13*
14*
*Voltage reading is dependent on the meter's impedance. Readings
may vary with different meters.
6. If voltage is not correct, replace processor board.
Step 8 − Thermistor Input Connector Checkout
1. Turn power to OFF position.
2. Remove the thermistor connections from pin terminal con-
nector J1, and mark them for later replacement.
3. Connect the negative test lead to test pin TP18.
4. Turn power to ON position, and enter the quick test
routine.
5. Place the other lead on terminals shown in Table 14, and
check the voltages.
6. If voltages are incorrect (per Table 14), replace processor
board.
7. Turn power to OFF position, and replace the thermistor
connections removed in Step 2.
8. Turn power to ON position.
27
VOLTAGE (DC)
2.5
5
5
2.5
2.5
5
2.5
2.5