Frigidaire CGMV173KB Servicing page 45

4. Disconnect the leads to the primary of the power
transformer.
5. Ensure that these leads remain isolated from other
components and oven chassis by using insulation
tape.
6. After that procedure, re-connect the power supply
cord.
After checking performance of the touch control
panel:
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. Reconnect the leads to the primary of the power
transformer.
4. Reinstall the outer case (cabinet).
5. Reconnect the power supply cord after the outer
case is installed.
6. Run the oven and check all functions.
a) On some models, the power supply cord between
the touch control panel and the oven itself is so
short that the two can't be separated. For those
models, check and repair all the controls (sensor-
related ones included) of the touch control panel
while keeping it connected to the oven.
b) On some models, the power supply cord between
the touch control panel and the oven proper is long
enough that they may be separated from each other.
For those models, it is possible to check and repair
the controls of the touch control panel while keeping
it apart from the oven proper; in this case you must
short both ends of the door sensing switch (on PWB)
of the touch control panel with a jumper, which
activates an operational state that is equivalent to
the oven door being closed. As for the sensor-related
controls of the touch control panel, checking them is
possible if dummy resistor(s) with resistance equal to
that of the controls are used.
Section 4 Component Teardown
B. Servicing the touch control panel with power
supply from an external power source:
Disconnect the touch control panel completely from the
oven proper, and short both ends of the door sensing
switch (on PWB) of the touch control panel, which brings
about an operational state that is equivalent to the oven
door being closed. Connect an external power source to
the power input terminal of the touch control panel, then
it is possible to check and repair the controls of the touch
control panel; it is also possible to check the sensor-
related controls of the touch control panel by using the
dummy resistor(s).
Servicing Tools
Tools required to service the touch control panel
assembly.
1. Soldering iron: 60W (It is recommended to use a
soldering iron with a grounding terminal.)
2. Oscilloscope: Single beam, frequency range:
DC - 10MHz type or more advanced model.
3. Others: Hand tools
Other Precautions
1. Before turning on power source of the control unit,
remove the aluminium foil applied for preventing
static electricity.
2. Connect the connectors of the key unit to the control
unit, being sure that the lead wires are not twisted.
3. After aluminium foil is removed, be careful that
abnormal voltage due to static electricity etc. is not
applied to the input or output terminals.
4. Attach connectors, electrolytic capacitors, etc. to
PWB, making sure that all connections are tight.
5. Be sure to use specified components where high
precision is required.
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