3.3V
0V
TROUBLE SHOOTING
1. POWER
1.1. The unit does not power on
YES YES
YES
NO
NO
YES
NO
NO
Does the power indicator
on the front panel î™±ash in
green when the power is
turned on?
Is a fuse blown?
Does the power display on
the front panel lights green
after approximately 10
seconds?
Check the voltage of pins 1,
5 - 7 of N1006 on the DIGI-
TAL PCB while the power
display is î™±ashing in green.
Remove the connector (BN501) of the MAIN PCB.
Check the "3.5. Protection history display mode"
(See page 44)
The unit does not power on
Is a fuse blown?
Does the power indicator on
the front panel î™±ash in red
when the power is turned on?
Is DC 5 V 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
from CN741 on the DIGITAL PCB and replace
any faulty parts.
To "3.5. Protection
History Display
Mode"
(See page 44)
Are there any parts not fully
connected into the connec-
tors that connect the PCBs?
Is DC5V output even when
the connector (CN741)
supplying power from the
SMPS PCB to the DIGITAL
PCB is removed?
Check the circuits around
the Microprocessor on the
DIGITAL PCB and replace
any faulty parts.
Check for breakages and short circuits
in the circuits and parts between
CN741 on the DIGITAL PCB and the
microprocessor power supply and
replace any faulty parts.
Connect the connectors cor-
rectly.
TO "6.SMPS"
(See page 85)
NO
YES
YES
YES
NO
NO NO
YES
Check for leaks and short
circuits in the parts on the
primary side. Replace any
faulty parts.
Blown fuse
Check the rectiî™°er diode in
the rectiî™°er 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
74
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