Remote Control & Front Switch Troubleshooting - Mitsubishi Electric LT-2220 Service Manual

MODELS: LT-2220 / LT-2240 / LT-3020 / LT-3040 / LT-3050
4. Other faults.(It applies both LT-30XX and LT-22XX)
Notes) It considers the case where there are problems except 1, 2, 3.
4-1. Remote control is not effective.
After checking the polarity of batteries, has
it loaded correctly?
YES
Regarding as the slide switch at the top of
the remote, does it set as "TV"?
YES
Does it use within 20 feet?
YES
It does not operate, even if it exchanges for
new batteries.
YES
When it pushes the remote switch, is the
signal below available at pins 1, 2, of J301
(remote switch use) ?
2:
1
YES
Skip to "4-2 front switch is not effective".
4-2. Front switch is not effective.
Is the following harness connected correctly?
· Between PWB-MAIN and PWB-CONT
(J301-J0A1)
YES
When it pushes the front switch, is the signal
below available at pins 1, 4, 5 of J301
(remote control and front switch use) ?
4, 5 : 3Vp-p only when switch is not pushed.
0V only when switch is pushed.
1
YES
IC300 (and peripheral circuits) are out of order.(PWB-MAIN)
NO
NO
NO
NO
NO
3Vp-p
3Vdc
NO
NO
3Vdc
Load the batteries, making sure the
polarities (-) and (+) are correct.
It sets the slide switch as "TV".
it uses within 20 feet.
It exchanges on new batteries.
Problem is in the following
PWB (and peripheral circuits).
Pin with PWB
problem including
the circuit
in problem
2 of J301 CONT
1 of J301 MAIN
Poor harness connection or
defective cable.
Problem is in the following
PWB (and peripheral circuits).
Pin with PWB
problem including
the circuit
in problem
4, 5 of J301 CONT
1 of J301 MAIN