Panasonic SA-XR700EG, Service Manual, Page: 21 / 145

6 Self Diagnosis Display Function
This unit is equipped with the self diagnosis display function, which alarms faulty operation with error code. Use this function during
servicing.
6.1. Automatically Displayed Error Codes
An error code automatically appears on the display (LCD) when faulty operation is detected. Refer to Fig. 6.1.
Fig. 6.1
6.2. Display Details
Refer to the following table.
LCD display Symptom Cause and Remedy
OVERLOAD Speaker short, amplifier failure Speaker short and failure in power
amplifier, pre-amplifier circuits. Check for
faulty parts and replace with new parts if
necessary.
Humidity protection activated
F70 Communication error between sub micro-
processor and its peripheral LSI Failure sub-micro processor and its
peripherals LSI. Check for faulty parts and
replace with new parts if necessary.
F76 When the power is turned on, the unit
power automatically turns off; the power
cannot be turned on. Failure in the power circuit system of the
unit. This may happen when the direct
current electricity is supplied to speaker
terminals. Check for the above and replace
with new parts if necessary.
6.3. Overload/Shutdown Detection intenal Condition
It detects OVERLOAD, POWER MALFUNCTION with [THRM_DET], [SHORT_DET] and [DC_DET] input port. It detects the
following condition depending on the input of the port as below table.
(H: DC ± 5V / L: DC ± 0V)
PROT Detection of malfunction Display and operation
SHORT_DET THRM_DET DC_DET
H L H Normal -----
H H H High Temp Refer to ´THERMAL PROTECTION´
L L H Speaker Short, Malfunction of Amplifier [OVERLOAD] / POWER OFF
L H H Detection of THERMAL PROTECTION
- - L Detection of POWER MALFUNCTION [ _ _ _ F76 _ _ _ ] / POWER OFF
6.4. Overload/Thermal Detection Display
When overload is detected, automatic POWER OFF will occur. But if any key on the remote control other than the [POWER] key
is pressed before that (including the [HELP] key), the scroll display will show [SWITCH_OFF_POWER]. Then, 1 second after
display of message, [OVERLOAD] will be shown on the scroll display.
6.5. Activating Self Diagnosis Function (Servicing Mode)
This mode can be used during servicing.
1. Plug the AC adapter to the power source. Press and hold down the [ENTER] button and the [SPEAKERS A] button, and then
press the [POWER] button at the same time.
2. The message, [SERVICE] appears on the display for three seconds, and then it will display the following. Refer to Fig. 6.2.
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SA-XR700EG