Power Soak 37179 PS-275 Service Manual - Manual (Page 30)

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6.9 Push Button Membrane
The buttons and lights on the front of the control panel are made into a plastic
membrane that is sandwiched between the plastic overlay and the sheet metal face of
the enclosure cover. Multiple “ribbon cables” attach to the buttons and lights. The
ribbon cables fit through a slot in the sheet metal door on the control panel and the
cables pug into the Membrane Encoder (see section 6.1b) to allow the buttons to signal
the UPM for the Start, Stop and Unload functions. The large connector ribbon cable
allows the UPM to illuminate the lights on the membrane. The membrane and overlay
are bonded to the sheet metal with an adhesive. If the membrane malfunctions, the
overlay and the membrane will both have to be replaced. The adhesive is strong
enough that the membrane and overlay cannot be removed without damage to both
components. The following illustrations show how to check the operation of the push
buttons.
Disconnect the large and middles size ribbon connectors and apply the leads of an ohm
meter to the middle size connector as shown. If the ohm meter does not show
continuity when the button is pressed and a break in continuity when the button is
released then the membrane must be replaced.
The large connector is unplugged to allow access to the middle size connector. The
large connector carries the signals to all the lights in the membrane except the POWER
light. The small connector carries the 24VAC to the POWER light. The small connector
is plugged into the wire harness, which is not part of the Membrane Encoder.
Orientation of the small connector to the wiring harness connector is not important.
START BUTTON
First and second from the
right side of the connector
as viewed in this photo
STOP BUTTON
First and third from the
right side of the connector
as viewed in this photo
UNLOAD BUTTON
First and fourth from the
right side of the connector
as viewed in this photo
Ohm meter probes Ribbon connector disconnected from the encoder