The
table below describes various symptoms that can occur if there is a short on
any of the power supply lines. These types of problems occur when major
components being supplied fail by shorting. An example would be if the audio
amp were to fail the set might shut down as if the Audio B+ line were shorted.
Many
times observing all the symptoms can lead you towards the correct failed
component or problem. All of your senses should be used when troubleshooting.
What you see, hear and smell can often lead you to quick fix.
Power supply voltages & distribution
Power supply voltages & distribution
|
Shorted Supply
|
Distribution
|
|
+135
|
A Board - T503
Flyback, H Drive Q501, H Out Q502, Pin Amp Q512, WA board VM Drive Q946.
|
|
+12
|
A Board - Q301 HP
Buffer, IC353 SHP, All WA board except VM Drive.
|
|
+9
|
A board - TU102 Tuner, IC351 VM Mute,
IC352 YUV Switch, IC354 YUV Switch, IC355 Y/C Jungle, IC101 D/A
Converter, AK Board - IC1401 Audio
Processor, IC1403 SRS, Q1102 Tuner 5 Volt Regulator, C Board - Q1790 IK
Buffer, UY Board - IC2006 5 Volt
Regulator, IC3302 5 Volt Regulator, IC3304 Chroma Decoder, IC3308 YUV Switch,
UY Board IC2005 3.3
Volt Regulator, IC2006 5 Volt Regulator for tuners.
|
|
UY5 from IC2006
|
IC3504 Comb Filter.
|
|
UY5 from IC3302
|
IC3307 V Chip,
IC3303 PIP Processor.
|
|
Audio B+ (33
Volts.
|
AK Board - IC1461
Audio Output.
|
Voltage
|
Relay
clicks
|
Video
|
Audio
|
Timer
LED
|
HV
|
Power
Switch Off
|
Suspect
|
+135
|
2 clicks very
close
together
Power Only
|
None
|
None
|
Blinking
|
None
|
No relay
click but
Timer LED
stops
Blinking.
|
Q502 H Out,
T503
Flyback, Q512
Pin
Out.
|
+12
|
1 click.
Power relay
only.
|
IK lines
visible.
OSD expanded
almost off
screen.
|
OK
|
Normal
|
OK
|
Unit shuts
off
Normally.
|
WA board
problem
or Q301 or
IC353 on
A Board.
|
+9
|
2 clicks
Power Relay
and Degauss
relay.
Degauss relay
never
turns OFF.
|
None
|
None
|
Blinking
|
None
|
Both relays
turn
OFF and Timer
LED
stops
blinking.
|
Regulators on
A
Board.
|
B+
|
Normal
|
Normal
|
None
|
Normal
|
Normal
|
Normal
|
PS1461 AK
Board
|
+200
|
2 clicks very
close
together
Power Only.
|
None
|
None
|
Blinking
|
None
|
No relay
click but
Timer LED
stops
Blinking.
|
IC1761 CRT
Amp.
Disconnect
CN1764
to verify.
|
+12
|
3 clicks. 2
Normal but then an extra
click
indicating
shutdown.
|
None
|
None
|
Blinking
|
None
|
No clicks
|
IC561: Vertical Output. Check R537.
|
- 15
|
2 clicks.
Power and
Degauss.
|
None
|
None
|
Blinking
|
Starts to come
up but stops
after 2nd click.
|
2 clicks when
set is turned OFF.
|
IC561
Vertical Output. Check
R536
|
Converter
not
switching
|
1 click.
Power Relay
only.
|
None
|
None
|
Blinking
|
None
|
1 click.
Power Relay
only.
|
IC601 and/or
R607
|
