TROUBLE SHOOTING
1. POWER
≧ 1.4V
1.1.   The unit does not power on
Does the power indicator on the front panel ash 
in green or white when the power is turned on?
Does the power display on the front panel lights 
green or white after approximately 8 seconds?
Check the voltage of [CN754 : 1, 5pin] on the 
DIGITAL PCB while the power display is ashing in 
green or white.
Check the voltage of pins 7 of [CN754] on the 
DIGITAL PCB while the power display is ashing in 
green or white.
Remove the connector [BN501] of the MAIN PCB.
Check the "3-2. Protection History Display Mode"
The unit does not power on
Is a fuse blown?
Is DC 5.2V being supplied from the SMPS PCB 
[BN601] to the DIGITAL PCB?
See "1.2. Fuse is blown"
See "1.2. Fuse is blown"
Check the circuits around the Microprocessor on 
the DIGITAL PCB and replace any faulty parts.
TO "3-2. Protection History 
Display Mode"
Are there any parts not fully connected into the 
connectors that connect the PCBs?
Is DC 5.2V output even when the Board in wire 
[BN601] supplying power from the SMPS PCB to 
the DIGITAL PCB is removed?
Check the circuits around the Microproces-
sor on the DIGITAL PCB and replace any faulty 
parts.
Check for breakages and short circuits in the cir-
cuits and parts between [CN741] on the DIGITAL 
PCB and the microprocessor power supply and 
replace any faulty parts.
TO "6. SMPS"
YES
0V 3.3V
0V
Check for leaks and short circuits 
in the parts on the primary side.  
Replace any faulty parts.
Blown fuse
Check the rectier diode in the 
rectier circuit on the secondary 
side, and check for short circuits. 
Replace any faulty parts.
Replace the fuse after repair.
Check for short circuits between the 
regulator output terminal and GND 
in the power supply stabilization 
circuit.  Replace faulty parts if there 
is a short circuit.
1.2. Fuse is blown
NO
NO
NO
YES
NO
YES YES
NO
YES
Does the power shut down after several seconds?
YES NO
NO YES
YES
Is a fuse blown? Connect the connectors correctly.
NO
s
65
Caution in 
servicing
Electrical Mechanical Repair Information Updating