Troubleshooting Guide Part - Panasonic SC-TM72DV Service Manual

13.1.1 Troubleshooting Guide Part 1

Checking Points Possible Faults
AC Inlet 1. Failure to power-up the main unit.
Circuit/Voltage 2. Power On switch
Selector Circuit
3. Intermittent Power supply to main
unit.
Transformer 1. No power supply voltage to the Power
Circuit Circuit from AC In.
Power Circuit 1. No supply voltage to Power Supply
Circuit from Transformer Circuit.
(+VccL/+VccH/-VccL/-VccH)
1. No supply voltage to Main & Power
Supply Circuit from Transformer
Circuit. (+VccL/+VccH/-VccL/-VccH)
1. No supply voltage to Panel Circuit.
Possible Reasons
• •
Wrong selection of
AC power to main
unit.
•
•
Voltage selector is
faulty.
•
•
AC inlet JK500 is
faulty.
•
•
AC Line filter L500 is
faulty.
•
•
Power On switch
broken.
•
• •
Check for connection.
• •
Transformer no output
voltage.
• •
Power Line filter
relay RL502.
•
D950 open circuit.
• •
Fuse F3/F4 blown.
• •
Rectifier Circuit
problem.
• •
Rectifier Circuit
problem.
•
•
F5801/FP5802 open
circuit.
• •
Q5815/D5835 faulty.
(-VP voltage not
sufficient to power FL
display at - 30V)
•
•
Q5816/D5839 faulty.
(Sys 6V not sufficient
to power micro-
processor IC at 6V.
Countermeasure
Replace of fuse if found faulty.
Replace of voltage selector if found
faulty.
Replace of AC Inlet if found faulty
or damaged.
Replace AC Line filter is found
faulty or damaged.
Replace Power On button switch if
necessary.
If conditions as mentioned above is
in good condition. Check for wire
connection.
(W1/W2/W3/W4/W6/W7). If
connection is good, please proceed
to check for Transformer Circuit.
If condition 1 to 4 as mentioned
above is in good condition. Check
for wire connection.
(W1/W2/W3/W4/W6/W7). If
connection is good, please proceed
to checkfor Transformer Circuit
Replace of Transformer T501 if
found faulty.
Replace of Power Relay if found
faulty.
Replace fuse F3/F4 if found faulty.
Replace
D5832/D5831/D5846/D5847 if any
is found to be faulty or damage.
Replace D5844 if found faulty.
Replace FP5801/FP5802 of the
same type as indicated in the part-
list if found faulty.
Replace Q5815/D5835 if found
faulty.
Replace Q5816/D5839 if found
faulty.