York YCAL0080SC Manuale Utente

YORK INTERNATIONAL

FORM 150.62-NM1

The operator keypad is connected to the microboard
by a ribbon cable, which is connected to J2 on the mi-
croboard.

The integrity of a specific “button” on the keypad can be
verified by doing a continuity check across two specific

FIG. 9 – MICROBOARD RELAY CONTACT

ARCHITECTURE

LD03842

TABLE 49 – KEYPAD PIN ASSIGNMENT MATRIX

STATUS

1 TO 5

OPER DATA

1 TO 7

PRINT

1 TO 6

HISTORY

1 TO 8

UP ARROW

2 TO 5

DOWN ARROW

2 TO 7

ENTER/ADV

2 TO 6

COOLING SETPOINTS

2 TO 8

SCHEDULE/ADVANCE DAY

3 TO 5

PROGRAM

3 TO 7

OPTIONS

3 TO 6

CLOCK

3 TO 8

points (or pins), that represent one of twelve “buttons”
on the keypad.

Table 49 lists the key/pin assignments for the keypad.
Power to the microboard must be turned off, and
the ribbon cable disconnected from the microboard
prior to conducting the tests, or component dam-
age may result.

After the ribbon cable is disconnected from microboard,
ohmmeter leads are connected to the pins represent-
ing the specific “button” to be tested.  After connecting
the meter leads, the “button” being checked is pressed
and a reading of zero ohms should be observed.  After
releasing the “button”, the resistance value should be
infinite (open circuit).