Troubleshooting - Mitsubishi Electric JT-SB116JH-G-NA Handbook

10. Troubleshooting

Work precautions
• When servicing, be sure to recreate the malfunction two or three times before starting repairs.
• When servicing, always take care to keep proper footing.
• Before starting the service, always unplug the power cord from the outlet, or turn off the circuit breaker when
no power cord plug is provided. Sufficient care must be taken to avoid electric shock or injury.
• Make sure to connect the power supply wires correctly.
• When removing the circuit board, always hold it at both ends and remove carefully so as not to apply force
to the surface mounted parts.
• When removing the circuit board, be careful of the metal edges on the board.
• When removing or inserting the connectors for the circuit board, hold the entire housing section. Never pull
on the lead wires.
• When circuit board failure is considered to be a cause, check closely for any broken section on the copper
foil patterns, burning or discoloration of parts.
• After replacing a circuit board, make sure to restore the same settings as before the replacement.
Description of the error mode display
Power LED Heater LED
: ON : Slow blinking (ON for 0.4 seconds/ OFF for 0.4 seconds)
: OFF : Fast blinking (ON for 0.1 second/ OFF for 0.1 second)
Troubles with error display
Error Mode Display
Power Heater
(Fuse is blown)
Checkpoint
Power supply Check that the circuit breaker is turned ON and that approx. 120 V
voltage AC is supplied at both ends of the power cord connections on the
terminal block.
■ If 120 V AC is not supplied, check the following point.
Check that the power cord is connected securely to the terminal
block.
Power supply Check that approx. 120 V AC is supplied between TAB1 and TAB2
voltage on the (orange) on the power circuit board (JT-34P1H).
power circuit
board (JT-34P1H)
●If 120 V AC is not supplied, check the following points.
Power supply Check that approx. 120 V AC is supplied to the following points in
voltage on the the order of 1 and 2.
filter circuit board 1 Between TAB20 and TAB21 (red)
If approx. 120 V AC is not supplied, check the connection from
(JT-34F)
the circuit breaker.
2 Between TAB22 and TAB23 (orange)
If approx. 120 V AC is not supplied, replace the filter circuit
board (JT-34F).
●When 120 V AC is supplied, check the following points.
Connector dis- Check if the connector CN19 on the display circuit board (JT-30S5)
connection for or CN18 on the control circuit board (JT-30M4/JT-30M4A) is dis-
the display circuit connected.
board (JT-30S5)
Connector discon- Check if the connector CN2 on the power circuit board (JT-34P1H)
nection between or CN5 on the control circuit board (JT-30M4/JT-30M4A) is discon-
the circuit boards nected.
Check Method and Remedy
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