SR-PE55LTQ - Panasonic Home Appliance Service Manual (repair manual). Page 9

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6.  Fault Diagnosis Methods

•  When providing maintenance service, please inquire about the fault (event) carefully.
•  When diagnosing the fault of a single component, be sure to remove the power plug from the socket.

6.1  How to Consult the Fault Diagnosis Table

The Fault Diagnosis Table falls into 6.3: Fault Diagnosis Table—Volume 1 (Body) and 6.5: Fault Diagnosis Table—
Volume 2 (Control Panel). Based on the fault diagnosis steps, first check 6.3: Fault Diagnosis Table—Volume 1 
(Body). If no applicable item is found, please go into 6.4: Simple Test for Control Panel Confi rmation. In case of 
abnormity, please refer to 6.5: Fault Diagnosis Table—Volume 2 (Control Panel) for fault diagnosis.
Specifi c fault state may be exhibited on the Fault Diagnosis Table in the form of breaking points (components).

6.1.1  Attentions for control panel operation

This microcomputer is provided with the MOS-type FET of CMOS Digital IC as the basic component. This type of 
microcomputer may suffer insulation breakdown due to cloth and human body, etc. or electricity leakage of soldering 
iron.
•  Grounding via resistor of several MΩ.
•  Use the soldering iron without grounding insulation fault, of which the soldering iron used for electronic component 

is the most suitable.

•  When operating component, do not touch the pins directly, and do not place the component on live conductor.
•  Do not insert components upside down on the printed circuit board.
•  When checking conduction with tester, do not use a high-resistance measuring range (X10000). It is acceptable to 

apply an electric pressure exceeding the rated value.

•  Welding must be done within a short period. (Within a few seconds.)
•  Please remove the power plug before replacing relevant component.
•  When the control panel is connected to AC 220V, touching the control panel shall exercise extreme caution to 

avoid electric shock.

6.2 Self-Diagnosis 

Function

In case of abnormal mode, the LCD (components of Liquid Crystal Display) will automatically display contents as 
below:

6.2.1  Diagnosis contents (U code)

Indication contents

Signs • Situation

Operation methods

“No pot” 
Incapable of cooking or keeping warm.

Put the pot in.

Keep Warm stops due to “excessive 
keep warm duration” in the keep warm 
period.

The keep warm lasts for 24h or even 
longer.

Press the “Power Off” key.
•  Does the keep warm function last 

for 24h or longer? (The duration 
of heating in keep warm mode 
is no more than 24h, and the 
maximum warm keeping period is 
recommended not to exceed 1h.)

6.2.2  Diagnosis contents (H code)

Indication contents

Signs • Situation

Operation methods

The “sensor disconnects” and receives 
no key-press operation.

Replace the cooker sensor.

The “relay shows abnormity” and 
receives no key-press operation.

Replace the control panel (power-
supply components) or the heater 
(whole).

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2014-3-14   9:12:39