Carrier 50FK, JK034-074, 48FK Ð Relay Board Pin Terminal Connector J9, Ð Voltage Reading

Step 5 Ð Check Relay Board Outputs from the Processor Board Ð This step involves checking the output signals from relays K1-K3 on the relay board.

1.Turn power to OFF position.

2.Connect negative test probe to TP19 (meter still set to dc).

3.Turn switch to ON position and enter Quick Test mode.

4.Connect positive test probe to terminal 14 on pin termi- nal connector J9, and check voltage from TP19 to ter- minal 14 on pin terminal connector J9.

5.If not 112 ± 1 vdc, replace processor board.

6.Turn switch to OFF position.

7.Remove negative test probe from TP19. Connect positive test probe to TP15.

8.Turn switch to ON position and go into Quick Test mode.

9.Place negative lead on terminals shown in Table 23, and check voltage between TP15 and terminals shown in Table 23 on pin terminal connector J9. See Fig. 50 for J9 details.

Fig. 50 Ð Relay Board Pin Terminal Connector (J9)

Table 23 Ð Voltage Reading

QUICK TEST					J9 PIN NUMBERS
STEP NO.	1	2	3	4	5	6	7	8	9	10	11	12	13
1.-2.3.	0	0	0	0	0	0	0	0	0	0	0	0	12
2.4.	0	0	0	0	0	0	12	0	0	0	0	0	12
2.5.	0	0	0	0	0	0	0	12	0	0	0	0	12
2.6.	0	0	0	0	0	0	0	12	0	12	0	0	12
2.7.	0	0	0	0	0	0	0	12	0	0	12	0	12
2.8.	0	0	0	0	0	0	0	12	0	0	0	12	12
2.9.	12	0	0	0	0	0	0	12	0	0	0	0	12
3.0.	0	12	0	0	0	0	0	12	0	0	0	0	12
3.1.	0	0	12	0	0	0	0	12	0	0	0	0	12
3.2.	0	0	0	0	12	0	0	12	0	0	0	0	12
3.3.	0	0	0	0	0	12	0	12	0	0	0	0	12

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 stay in the Quick Test routine for 10 minutes unless the display button is pressed.

2.Acceptable range for the voltage reading:

0 v Ð 0 to 4 v

12 v Ð 11 to 13 v

3.If any of these voltages are not measured, replace the processor board.

Step 6 Ð 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. 51 for pin terminal connector J10 details):

PIN TERMINAL	VOLTAGE (DC)
17	5
18	5
20*	2.5
22*	2.5
24	5

*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 7 Ð 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	VOLTAGE (DC)
1*	2.5
3	5
6	5
8*	2.5
10*	2.5
12	5
13*	2.5
14*	2.5

*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 24, and check the voltages.

6.If voltages are incorrect (per Table 24), replace processor board.

7.Turn power to OFF position, and replace the thermistor connections removed in Step 2.

8.Turn power to ON position.

Fig. 51 Ð Display Board Pin Terminal Connector (J10)

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