Main Troubleshooting Flow Chart

CTC203
TROUBLESHOOTING
Main Troubleshooting Flow Chart
Dead Set
7-2
EEPROM Error Codes
7-3
System Control
7-4
Power Supply
7-5
Horizontal
7-6
Vertical
7-7
Tuner
7-8
Tuner Band Switching
7-9
Color
7-10
Video
7-11
Buttons
7-12
Infrared
7-12
OSD
7-13
Gemstar
7-14
F2PIP
7-15
Analog Comb
7-16
General Audio Problems
7-18
Distorted Audio
7-20
Stereo Seperation
7-20
No Stereo
7-21
Sound Logic
7-22
Page 7-1
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
DEAD SET TROUBLESHOOTING
Set Will Not Turn On
Degauss Relay
Switching
YES
ON/OFF?
Check EEPROM Error Codes
Using Chipper Check
NO
Microprocessor
U13101 Reset YES
Pin 51 = 5V?
Check System Control
NO
Check Power Supplies
Page 7-2
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
EEPROM Error Codes
Error code:
HEX
Chassis:
DEC
0
1
3
8
9
10
11
16
ALL
ALL
ALL
ALL
ALL
w/ F2PIP
ALL
ALL
12
18
ALL
DEC
34
44
102
128
160
186
196
198
Action
POWER CONTROL ERRORS
00
01
03
08
09
0A
0B
10
HEX
22
2C
66
80
A0
BA
C4
C6
Error:
No Errors
16V_STBY fault
12V_RUN fault
T4chip XRP (X-ray protection)
T4chip POR (power on reset)
F2PIP POR
Stereo Decoder POR
Run I2C bus latched
Standby I2C bus latched
Check Power Supplies
Check Power Supplies
Check Power Supplies
Check Horizontal
Check F2PIP
Check General Audio
Check System Control
Check System Control
I2C ACKNOWLEDGE ERRORS
w/Gemstar
w/ F2PIP
w/Gemstar
ALL
EEPROM
ALL
ALL
ALL
Failure to get acknowledge from Gemstar module
F2PIP fault
Gemstar bus fault
Stereo Decoder fault
EEPROM bus fault
T4chip fault
Main Tuner PLL bus fault
Main Tuner DAC bus fault
Page 7-3
Check Gemstar
Check F2PIP
Check Gemstar
Check General Audio
Check System Control
Check System Control
Check Tuner
Check Tuner
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
System Control Troubleshooting
Microprocessor
U13101
Pin 51 = 5V?
NO
YES
EEPROM
U13102
Pin 8 = 5V?
NO
Check Micro Reset Circuit.
Q13501, Q13503, etc.
U13101
Pin 20 ~4.5V? NO
YES
YES
Check R13128,
R13181,Q13104.
U13101 Pin 20
should be High
Impedance. If
not replace.
Replace Q13104
Microprocessor
U13101
NO
Pins 40,42 = 4MHz?
Replace 4MHz Crystal Y13101,
R13107,C13106,C13107
YES
Plug in AC. Check Bus
Activity on U13101 Pins
23,24. Do Transmissions NO
Stop after a few moments?
Check EEPROM and Power
Supplies
YES
Microprocessor
U13101 KD1
Pin 5 = 5V Pulse?
NO
Check Power Supply
YES
Note: Pin 5, Drive
Line, should have a
20ms pulse. If this
pulse is seen on a
sense line then a
button is closed.
Microprocessor
U13101 Sense Lines
Pins 6,7,8 = Steady NO
5V with No pulses?
Check Front Panel for Stuck or
Shorted Button or Missing 5V.
YES
Check EEPROM Error Codes
Using Chipper Check
Page 7-4
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Power Supply Troubleshooting
Raw B+
@TP14210
~ 150V ?
NO
Check F14201, R14202,
CR14201-CR14204
YES
+16V stanby
Cathode CR14108
~ 16V?
NO
Check CR14108
YES
RegB+ Cathode
CR14106
~ 130V?
NO
Check RegB+ Circuit. R14116,U14101,U14102,
Q14102,Q14103,Q14106,Q14107,Q14101
YES
+5V stanby
U14103 Pin 3
~ 5.2V?
U14103 Pin 1
~ 14.8V? NO
NO
Check CR14110
YES
YES
Replace Q14104,Q14105
Replace U14103
If the Degaus
Relay is clicking
then the +12Vs
and +7.5Vs will
be ON only
momentarily at
turn ON.
+12V Switch
U14104 Pin 3
~ 12.2V?
U14104 Pin 1
~ 16V? NO
NO
YES
YES
Replace U14104
+7.5V Switch
U14150 Pin 3
~ 7.3V?
U14150 Pin 1
~ 10V? NO
NO
NO
Troubleshoot System
Control
Check R14151
YES
YES
Power Supplies OK
YES
U13101 Pin 19~5V
with Power Button
Pressed?
Replace U14150
Page 7-5
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CTC203
TROUBLESHOOTING
Horizontal Troubleshooting
NOTE:
If the Set is going into XRP shutdown the Degaus Relay will click
and the pulses below will only be present momentarily at turn ON
T4 Chip
U12101
Pin20 =7.6V?
NO
Check U14150
NO
T4 Chip U12101
Bus Activity on
Pins 43, 44?
YES
T4 Chip U12101
Pin 22 =7.2Vp-p
Square Wave?
YES
Q14302 Emitter
= 5.3Vp-p
Square Wave?
NO
YES
Troubleshoot
System
Control
Replace U12101
(See Note at Top)
NO
Replace Q14302
NO
Replace Q14301
YES
Q14301Collector
= 224Vp-p ?
YES
Q14401 Base
~ 3.1Vp-p?
NO
Replace
T14301
Check Base Components
NO
YES
EEPROM Code
indicates XRP
Fault?
NO
YES
YES
Q14401
Collector
= 1060 Vp-p?
With Set OFF is
there Continuity
in T14301?
NO
Check Bad Q14401, Shorted or open
T14401, Bad Horizontal Yoke Winding.
Check C14403, CR14403 and RegB+.
Horizontal Test
Complete
YES
Check XRP Circuitry Q14901, CR14902,
R14902, R14903, R14905
Page 7-6
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Vertical Troubleshooting
T4 Chip U12101
Pin 15 ~2.4V
Sawtooth ?
NO
T4-Chip
U12101 Pin
NO
26 =7.6V?
Check U14150
T4-Chip
U12101 Pin
NO
20 =7.6V?
Check R14153
YES
YES
YES
Reinitialize EEPROM Vertical
Settings. Replace U12101 if Reinit
doesn't work
U14501 Pin 1
~2V Parabola ?
Replace RN14501
NO
YES
U14501
Pin 2 ~ 23V?
Troubleshoot Power Supply
NO
YES
U14501
Pin 6 ~ 23V?
NO
Check CR14501
NO
Replace U14501
NO
Replace U14501
YES
U14501
Pin 3 ~ 1.5V?
YES
U14501 Pin 5
~50V Vertical
Ramp?
YES
Check Connection P14501
and Choke Continuity
Page 7-7
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CTC203
TROUBLESHOOTING
Tuner Troubleshooting
NOTE: If the GEMSTAR is set up to use a DSS or Cable Box the Tuner may be locked
to the input channel for that device. The OSD will still show a channel change but the
Channel DOES NOT change therefore the tuning voltages will NOT change
Check Supplies to Tuner.
+5,+9,+12,-12,+33
All Supplies
Present?
NO
Troubleshoot Power Supplies
YES
Does OSD
Change?
Does Set Tune? NO
YES
Troubleshoot
Control System
NO
YES
See Note at Top of page
Goto Band Switch
Troubleshooting
on next page.
U17401 Pins18,19.
Is There Bus NO
Activity?
Do All Bands
NO
Tune?
YES
Check U12101
Pin 5 and
components in
AGC Line.
Troubleshoot
Control System
YES
See Note at Top of page
U17401 Pins 5,6,7,8.
Are Voltages Close NO
To Voltage Chart?
Does AGC Voltage
NO Change when Input
is Attenuated?
Replace U17401
YES
YES
U17301 Pin 11.
Does Voltage
NO
change with
Bands?
Replace Q17402
Does AGC Voltage
Change when Input NO
is Attenuated?
Replace U17301
Use Chipper Check to
Check Tuner alignment
and EEPROM Values
YES
YES
Troubleshoot Video
Page 7-8
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Tuner Troubleshooting (continued)
Troubleshoot Band Switches
Check Supplies to Tuner.
+5,+9,+12,-12,+33
See Note at Top of previous page
U17401 Pins 5,6,7,8.
Are Voltages Close NO
To Voltage Chart?
Replace U17401
YES
Q17404
Switching
NO
Voltages Correct?
Replace Q17404
YES
Q17402
Switching
NO
Voltages Correct?
Replace Q17402
YES
Set Tunes
Band 3?
NO
YES
Set Tunes
Either Band
1 or 2?
NO
YES
Replace CR17101, CR17114,
CR17102, CR17103, CR17301,
CR17304 & Q17101
Q17403
Switching
NO
Voltages Correct?
Replace Q17403
YES
Check Diodes CR17105, CR17112,
CR17109, CR17110, CR17303.
Replace as needed
Page 7-9
Replace CR17106, CR17107,
CR17108, CR17111, CR17113,
CR17302 & Q17102.
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Color Troubleshooting
No Color
U12101 Pin 42
Color Burst >
200mV?
Check Input Signal strength.
Troubleshoot Tuner if strong
signal is attached to input.
NO
YES
U12101 Pin 40
Color Burst >
100mV?
NO
Troubleshoot Video Module
YES
NOTE: Color Killer is active if Pin 39 ~1.5V
U12101 Pin 39
Color Killer
~3.5V?
NO
Check R12801, R12802, R12804 and
C12801. If components are good
Replace U12101
U12101 Pin 13
Chroma APC
~5.5V?
NO
Check attached components and for
7.6VrA
U12101 Pin 41
Test Filter
~5.5V?
NO
Check attached components and for
7.6VrF
YES
YES
YES
Replace U12101
Page 7-10
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Video Troubleshooting
No Video
U12101 Pin 42
~ 2Vp-p?
NO
Check Input Signal strength.
Troubleshoot Tuner if strong
signal is attached to input.
NO
Troubleshoot Video Module
(F2PIP or Analog Comb)
NO
Replace U12101
YES
U12101 Pin 38
~ 1Vp-p-?
YES
U12101 Pin 30,
31,32 ~ 2.5Vp-p
Video Signal?
YES
Video present at
collectors of
Q12701, Q12702, NO
Q12703?
Replace Faulty Transistors
YES
Check that pins in connector are soldered properly.
12VrK Present at
bases of Q12701,
Q15102, Q15103?
NO
Troubleshoot 12V supply
YES
Video present at
collectors of
Q15101, Q15102, NO
Q15103?
Replace Faulty Transistors
YES
Check the CRT Screen
Control and that the
Filaments are glowing.
Page 7-11
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
User Interface Troubleshooting
If a Button is shorted or stuck closed the set will not
respond to either the Remote Control or Button Press.
Set does not respond to some
button presses.
U13101Pin5
~ 20ms Square
Wave?
NO
Troubleshoot System Control
NO
Check 5V and R13113,
R13118, R13119.
YES
U13101 Pin 6,7,8
= 5V?
YES
When Power, Volume Up, or Volume Down is pressed there should be ~20ms
low pulse on their respective sense line. If pulse is not present check for a
bad switch. If Channel Up, Channel Down or Menu is pressed their respective sense line should go Low for the duration of the button press. If not
check for a bad switch.
Set does not respond to
Remote Control.
Set Responds to
all buttons?
NO
Troubleshoot Buttons
NO
Troubleshoot Power Supply
YES
5V at VCC Pin of
IR receiver?
YES
~5Vp-p Transmission at Output Pin NO
of IR receiver?
Replace IR Receiver
YES
Troubleshoot System Control
U13101 Pin 36.
Page 7-12
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
OSD Troubleshooting
Set does not have Channel
Numbers or Menus
U13101Pin 35
Horizontal
Present?
NO
Check Q13301
NO
Replace U14150
NO
Check Pin 3 U14150, JC14105,
13320, R13314.
NO
Replace U13101
YES
U14150 Pin 3 ~
1.5V?
YES
U13101 Pin 34
Vertical Present ?
YES
Press "Menu".
U13101Pin 26,
27,28 is OSD
Present?
YES
Press "Menu".
U12101Pin 34,
35, 36 is OSD NO
Present?
Check components between
U13101 and U12101
YES
If Video is normal replace U12101.
If Video is missing Troubleshoot
Video
Page 7-13
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
GEMSTAR Troubleshooting
Tune set to a channel with valid GEMSTAR program information on the
Vertical Blankin Interval (VBI). Gemstar is auto-detected by the microprocessor. Select the Main menu. If GEMSTAR has been detected there
will be a menu item "Guide Plus+ Menu".
Main Menu
displays "GUIDE
PLUS+ Menu" ?
Module Cables
seated Properly
?
NO
NO
If item is not present check
the cable(s) to the GEMSTAR
module to make sure they are
seated properly. Select the
menu again, item will show up
if this was the problem.
NO
Troubleshoot +5.2V network
and supply
NO
Check for proper components
and that all parts are soldered.
Replace Y26401.
YES
YES
+5.2V present
U26401 pins 12,
24, 31, 42, 51,
61, 65, 73?
YES
4.03MHz OSC
on U26401 Pins
66,67?
YES
Pulsed Bus
activity on U26401 NO
Pins 69, 70?
YES
Check bus lines and components and that all parts are
soldered.
Check U13101 pins 13,14.
Replace U26401
GUIDE Menu is
present ?
Vertical present on
U26405 pin 2 ? NO
NO
YES
YES
Vertical present on
U26401 pin 36 ? NO
Check line and components
back to J13103.
Troubleshoot Vertical.
Replace U26405
YES
Horizontal
present on
U26401 pin 39 ?
NO
Check Q26403
YES
NEXT PAGE
Page 7-14
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
GEMSTAR Troubleshooting (cotinued)
FROM PREVIOUS PAGE
U26401Reset pin
71 ~5.2V ?
NO
Check line to J13103.
Troubleshoot System Control
YES
Check components attached
to U26401pins 62,63. These
control the OSD dot clock.
RGB present
U26401 pins
48,49,50?
NO
Replace U26401
NO
Replace U26401
YES
FSW present
U26401 pin 53 ?
YES
Check Connector J13103
Troubleshoot Video
Valid Data
Stored in
GUIDE ?
YES
NO
Make sure set is tuned to GEMSTAR data provider. Select
"MainMenu", select "GUIDE Plus+ Menu", select
"GUIDE Plus+ Setup". On the Remote Control Press
"Go Back" and then "TV". This will bring up the Factory
Diagnostic Screen.
ROM Test
Passed?
NO
Replace U26402
NO
Replace U26403
NO
Tuned to Non-VBI channel?
Check Q26405 composite
Video also Q26404,Q26408
which supply sync during "set
off" downloads.
YES
RAM Test
Passed?
YES
VBI Test
Passed?
YES
Check Owners manual on GIUDE Plus+ Setup
procedures.
Page 7-15
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
F2PIP Troubleshooting
EEPROM Error indicates a
F2PIP error.
Does set turn
ON?
NO
YES
Set has a Main
NO
Picture?
YES
PIP Turns ON?
Check Y18100, 14.318MHz
crystal. Should be within 1Khz
of nominal to guarantee
proper operation
Check 3.3V supply.
Check Data and Clock Lines.
Check main Video Signal path.
If above is good replace U18100
NO
Check for proper Vert. &
Horz. Sync at U18100 Pin 24
NO
Check PIP contrast and
Brightness alignments.
Check PIP signal Path
YES
PIP Picture
Visible?
YES
PIP Picture
Distorted ?
NO
PIP Normal
YES
Use Chipper Check to check
PIP Alignments.
Page 7-16
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Analog Comb Troubleshooting
Connect a signal generator to the Tuner Input and to
the Video Input Jack. Check 5V and 12V supplies.
U26903
Pin 6 = TV
Video Signal
NO
Troubleshoot Video Signal
NO
Check R11406, C11403,
R26921
YES
U26903
Pin 3 = Input
Video Signal
YES
U26903 Pin 4
0V =TV Video NO
5.1V = Input Video
YES
Luma
U26903 Pin 8.
Signal can be
switched between TV
NO
Video and Input
Video?
YES
Luma & Chroma
present at Pins 3
& 5 on FL2601
Check Q26903 and insure that
switching voltage is present
from U13101
Replace U26903
NO
Replace FL2601
Chroma present at
Pin 8 U26902 NO
Replace U26902
YES
YES
Chroma
Luma present at
Pin 6 J26901
NO
Luma present at
Pin 8 U26901
NO
YES
YES
Analog Comb OK
Replace Q26901
Page 7-17
Replace
U26901
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
General Audio Troubleshooting
Connect a generator to the set. Adjsut "Sound Processor" Menu to "Speakers ON", Fixed Level Mode OFF", "Sound Logic OFF".
Sound Quick Checks:
1. Check that Speaker's plug is seated properly.
2. Check that the "Speakers" are turned ON & "Fixed Level Mode"is OFF
3. Check that Balance is Centered.
4. Check if there is audio present at Audio Output Jacks to isolate problem.
EEPROM Error
code indicates Audio
Problem.
Does set turn
ON?
Check 9V regulator Q11603.
Check U11601 Bus lines
Pins 9,10 .
NO
YES
Wide Band
Audio present at
Pin 17 U11601 ? NO
Check C11601, Pin 6 U12101
YES
U11601 Pin 39,
40 Audio
ABSENT ?
NO
YES
Check menu items again. Send
Volume Up Command.
U11601 Pin 22
Vcc~ 9.4V ?
NO
Check Q11603
YES
U11601 Pin 12, 13,
17, 39, 40 Bias NO
Voltage~ 4.1V ?
Replace U11601
YES
U11601 Pin 12,
13, Audio
Present ?
NO
Replace U11601
YES
Go To Next Page
Page 7-18
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Genearl Audio Troubleshooting (continued)
Set Volume To Max
U11601 Pins 7, 8
Audio Present?
U11601 Pins 1, 8
Bias ~4.1V? NO
NO
YES
Replace U11601
YES
Components
on U11601
Pins 1-4,7, 8
Correct?
NO
Replace with correct
components
YES
Replace U11601
U11602 Pins 1, 7
Audio Present?
U11602 Pin 8
~+8V and Pin 4
~ -8V ?
NO
YES
NO
Troubleshoot Power
Supplies
NO
Replace with correct
components
YES
Components
on U11602
Correct?
YES
Replace U11602
U11900/11901
Pin 2 Audio
Present?
+16V Supply
present ?
NO
YES
NO
Troubleshoot Power
Supplies
NO
Check Q11901, C11909,
U13101 Pin 2
YES
U11900/11901
Pin 3
>7V ?
YES
YES
U11900/11901
Pin 4 Audio
Present
( 71mVrms )?
NO
Replace U11900/11901
Check Connector J11901
Page 7-19
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CTC203
TROUBLESHOOTING
Audio Troubleshooting (Distortion)
Use a standard 1kHz or 3kHz Sine Wave as an input to the Audio System.
Scope Audio at HiFi or Speaker Outputs (whichever is failing) to determine
if distortion is visible. Move back along Audio signal path to determine
where distortion begins. If point of origin cannot be determined check the
things below.
Check for electrolytics installed backwards or solder shorts around U11601.
Anything that can cause shorts or improper bias on the IC pins. Check for
open traces or missing jumper wires.
Check values of R11704/11706. Excessive gain in Expanded Stereo can cause
Loop IN (U11601 Pins 41,41) to be overdriven. This can cause distortion in
All Modes.
Check voltages on Vcc pins at the Audio ICs as well as the power network
that supplies power to the audio circuit for proper voltage levels.
Check that the Pins of all Audio ICs are soldered properly. Unsoldered pins
can cause overheating and shutdown in the output devices.
If Speaker output is distorted but HiFi outputs are not then the problem is
probably in the U11900/11901 circuit area.
Check that coupling capacitors are loaded properly. Check for shorts
around U11900/U11901 and that the devices are not partially MUTED.
No Stereo Seperation
Problems with stereo seperation are mostly due to wrong, missing or backward parts around U11601. Specifically C11605, C11610 and other parts
connected to pins 16, 18, 23, 24, 28, 29, 30 and 34. this can cause failure of
one of the alignments.
Page 7-20
Return To Main Flow Chart
CTC203
TROUBLESHOOTING
Audio Troubleshooting (No Stereo)
Tune to a channel with known good strereo. Set SOUND PROCESSOR
mode to STEREO. Insure set is working with Mono audio signal.
Set OSD says
STEREO?
NO
U11601 not locked to strereo pilot or pilot
level to low. Check components at pins 14,
15, & 16 for correct values and proper
installation.
NO
Replace U11601
YES
Stereo signal
@ U11601 Pins
23, 24, 31&32?
YES
U11601 Pins
39,40 Stereo
Present?
NO
Use Chipper Check to view Stereo alignment
values. Values near one end of the alignment
range may indicate wrong or missing components. Noisy or improperly aligned SIF or
poorly aligned stereo alingment. Attempt to
realign.
NO
Check components at dbx pins for correct
values and proper installation. If components are correct Replace U11601
YES
U11601 Pins
14,15,16,19,28,29,30
&34 bias
correct?
YES
U11601 Pins 7,
8 stereo signal
both channels?
NO
Replace U11601
NO
Replace U11602
YES
U11602 Pins 1
& 7stereo
signal both
channels?
YES
U11900/11901
Pin 2, stereo
signal both
channels?
NO
Replace device without signal
YES
Check connector J11901, P11901
and speakers
Page 7-21
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CTC203
TROUBLESHOOTING
Audio Troubleshooting (Sound Logic)
Tune to a channel with strong MONO signal. Connect a DC
voltmeter to cathode of CR11503.
Voltmeter
reading ~4V ?
NO
YES
Check components around U11501 for
correct values and proper installation. Insure that there is a strong WBAudio Signal
at U11601 Pin 17.
Remove Audio input
Voltmeter
reading <100mV
?
NO
Check +12V and -12V supplies. Check for
missing parts, wrong values or solder problems. Replace U11501
NO
Check components in Sound logic line between U13101 pin 37 and CR11503
YES
U13101 Pin 37
Voltage same as
@ CR11503 ?
YES
Sound Logic OK
Page 7-22
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