Subzero WOLF ICB WS Series Service Manual page 70

Troubleshooting Guides
WINE STORAGE MEMBRANE SWITCH / RIBBON CABLE TEST PROCEDURE
The membrane switch is that part of the control panel assembly consisting of the function keys used for all input
functions to the electronic control system.
Perform the eight continuity checks below if the integrity of the membrane switch and/or its ribbon cable is suspect.
To perform these continuity checks, the ribbon cable must be disconnected from the control board.
NOTE: The wires of the ribbon cable are exposed at the back side of the terminal housing. With an Ohm Meter,
check for continuity at these exposed points/pins. Pin #1 is at top of the terminal housing, closest to the arrow on
the housing (see Figure 7-1).
1. Pressing no keys on the membrane switch; check for continuity across all pin combinations. With no keys
pressed, there should be no continuity.
2. With POWER key pressed, there should be continuity across pins #4 & #6 only.
3. With lower wine storage COLDER key pressed, there should be continuity across pins #2 & #3 only.
4. With lower wine storage WARMER key pressed, there should be continuity across pins #3 & #4 only.
5. With upper wine storage COLDER key pressed, there should be continuity across pins #2 & #6 only.
6. With upper wine storage WARMER key pressed, there should be continuity across pins #5 & #7 only.
7. With LIGHTS ON/OFF key pressed, there should be continuity across pins #5 & #6 only.
8. With alarm bell key pressed, there should be continuity across pins #3 & #7 only.
NOTE: If the membrane switch fails any of the above tests, the control panel assembly should be replaced. If all
tests are passed and the control panel is still inoperable, replace the control board.
With exposed points/pins on back side of
housing facing up, Pin #1 is at bottom
FAN RELAY CONTINUITY TESTS
With all wires disconnected from the fan relay, all pin
combinations should show as open circuits when
checked with an ohm meter, except for the following:
• Pin 1 to Pin 5 (continuity - fan circuit)
• Pin 4 to Pin 6 (continuity - light circuit)
• Pin 7 to Pin 8 (continuity - relay coil)
If the relay fails any of the continuity tests, replace the
relay.
#7013455 - Revision A - April, 2009
International W
International W
(See Figure 7-1)
Control Panel Assembly
Figure 7-1. Control Panel / Membrane Switch
7-14
ine Storage
ine Storage
(ICBWS)
(ICBWS)
1
3
5
7
Figure 7-2. Relay Layout
Series
Series
2
4
6
8