PROCESSOR BOARD CHECKOUT — Refer to Fig. 32
and 33 for location of terminal pins and test points.
Step 1 — Check transformer input to the board.
Connector J4 is used to connect the control transformer to
the processor board.
1. Set the volt-ohmmeter to ac voltage with a range setting
of approximately 30 v.
2. Turn control switch to ON position.
3. Check voltage at following terminals on pin terminal con-
nector J4:
TERMINALS
VOLTAGE (AC)
1 to 2
15.3 to 20.9
4 to 6
16.2 to 22.0
5 to 6
8.1 to 11.0
5 to 4
8.1 to 11.0
4. If voltage is not within range, check primary side.
115-v transformer — 104 to 127 vac
230-v transformer — 207 to 254 vac
5. If primary voltage is not correct, check system fuse, trans-
former, ON-OFF switch, and wiring. If these are okay,
contact power company.
6. If primary voltage is correct, but secondary voltage
(24 v ± 10%) is incorrect, replace transformer.
7. Turn control switch to OFF position.
Step 2 — Check processor board power supply.
1. Set meter to approximately 20 vdc.
2. Turn power to OFF position.
3. Connect negative lead to TP18.
4. Turn power switch to ON position and press display but-
ton to enter quick test mode.
5. Check voltage between TP18 and each of the following
test pins:
TEST PIN
VOLTAGE (DC)
TP3
1
10
TP4
1
12
TP6
1
5
TP10
1
5
TP14
1
12
TP15
1
12
TP7
−5*
*If not using a digital meter, leads must be reversed.
6. If voltage is incorrect, replace processor board.
7. Turn power to ON position.
Step 3 — Check voltage tolerance circuitry.
1. Turn power to OFF position.
2. Negative test probe on TP18 and system in quick test mode.
3. Check voltage TP18 to TP9.
4. If voltage is greater than
1
1 vdc, recheck transformer
input voltage.
5. If transformer is okay, replace processor board.
6. Turn power to ON position.
Step 4 — Check processor reset line.
1. Turn power to OFF position.
2. Negative probe on TP18.
3. Check voltage TP18 to TP11.
4. If voltage is greater than
1
3 vdc, reset power and re-
check.
5. If voltage is still incorrect, replace processor board.
6. Turn power to ON position.
Step 5 — Check relay board outputs from the processor board.
This step involves checking the output signals from re-
lays 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
1
12 ± 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 13, and
check voltage between TP15 and terminals shown in
Table 13 on pin terminal connector J9. See Fig. 34 for J9
details.
K1
K2
K3
C1
C2
C3
C4
C5
C6
C7
C8
CR1
CR2
CR3
CR4
CR5
CR6
CR7
CR8
C27
C15
C14
C26
C25
C24
C23
C22
E3
CR9
CR10
CR11
CR12
CR13
C9
C10
C11
C12
C13
R9
R10
R11
R12
R13
J5
J6
C19
C16
C18
C21
CR — Control Relay
J
— Pin Terminal Strip
K
— Relay
Fig. 33 — Relay Board Test Points
Q2
C14
CR5
R65
R13
E6
Z6
J7
TP19
J9
TP18
TP10
TP15
TP14
J10
J3
TP9
TP3
TP4
TP7
TP6
J4
TP11
J
— Pin Terminal Strip
TP — Test Pin
Fig. 32 — Processor Board Test Points
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