RCA CTC203 Schematic

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

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CTC203
TROUBLESHOOTING

DEAD SET TROUBLESHOOTING

Set Will Not Turn On

Degauss Relay

Switching

ON/OFF?

NO

Microprocessor

U13101 Reset

Pin 51 = 5V?

YES

YES

Check EEPROM Error Codes

Using Chipper Check

Check System Control

NO

Check Power Supplies

Page 7-2

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CTC203
TROUBLESHOOTING

EEPROM Error Codes

Error code: Chassis: Error: Action

HEX DEC POWER CONTROL ERRORS

00 0 ALL No Errors
01 1 ALL 16V_STBY fault Check Power Supplies
03 3 ALL 12V_RUN fault Check Power Supplies
08 8 ALL T4chip XRP (X-ray protection) Check Power Supplies
09 9 ALL T4chip POR (power on reset) Check Horizontal
0A 10 w/ F2PIP F2PIP POR Check F2PIP
0B 11 ALL Stereo Decoder POR Check General Audio
10 16 ALL Run I2C bus latched Check System Control

12 18 ALL Standby I2C bus latched Check System Control

HEX DEC I

22 34 w/Gemstar Failure to get acknowledge from Gemstar module Check Gemstar
2C 44 w/ F2PIP F2PIP fault Check F2PIP
66 102 w/Gemstar Gemstar bus fault Check Gemstar
80 128 ALL Stereo Decoder fault Check General Audio
A0 160 EEPROM EEPROM bus fault Check System Control
BA 186 ALL T4chip fault Check System Control
C4 196 ALL Main Tuner PLL bus fault Check Tuner
C6 198 ALL Main Tuner DAC bus fault Check Tuner

2

C ACKNOWLEDGE ERRORS

Page 7-3

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CTC203
TROUBLESHOOTING

System Control Troubleshooting

Microprocessor

U13101

Pin 51 = 5V?

YES

EEPROM

U13102

Pin 8 = 5V?

YES

NO

NO

Check Micro Reset Circuit.

Q13501, Q13503, etc.

U13101

Pin 20 ~4.5V?

Replace Q13104

YES

NO

Check R13128,

R13181,Q13104.

U13101 Pin 20
should be High

Impedance. If

not replace.

Microprocessor

U13101

Pins 40,42 = 4MHz?

YES

Plug in AC. Check Bus

Activity on U13101 Pins

23,24. Do Transmissions

Stop after a few moments?

NO

YES

Microprocessor

U13101 KD1

Pin 5 = 5V Pulse?

YES

NO

NO

Replace 4MHz Crystal Y13101,

R13107,C13106,C13107

Check EEPROM and Power

Supplies

Check Power Supply

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
5V with No pulses?

YES

NO

Check EEPROM Error Codes

Using Chipper Check

Page 7-4

Check Front Panel for Stuck or

Shorted Button or Missing 5V.

Return To Main Flow Chart

CTC203
TROUBLESHOOTING

Power Supply Troubleshooting

Raw B+

@TP14210

~ 150V ?

YES

+16V stanby

Cathode CR14108

~ 16V?

YES

NO

NO

Check F14201, R14202,

CR14201-CR14204

Check CR14108

If the Degaus

Relay is clicking

then the +12Vs

and +7.5Vs will

be ON only

momentarily at

turn ON.

RegB+ Cathode

CR14106

~ 130V?

YES

+5V stanby

U14103 Pin 3

~ 5.2V?

YES

+12V Switch

U14104 Pin 3

~ 12.2V?

YES

+7.5V Switch
U14150 Pin 3

~ 7.3V?

YES

NO

NO

NO

NO

Check RegB+ Circuit. R14116,U14101,U14102,

Q14102,Q14103,Q14106,Q14107,Q14101

U14103 Pin 1

~ 14.8V?

YES

NO

Check CR14110

Replace Q14104,Q14105

Replace U14103

U14104 Pin 1

~ 16V?

YES

NO

YES

U13101 Pin 19~5V

with Power Button

Pressed?

NO

Replace U14104

Troubleshoot System

Control

U14150 Pin 1

~ 10V?

YES

NO

Check R14151

Power Supplies OK

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?

YES

T4 Chip U12101
Pin 22 =7.2Vp-p

Square Wave?

YES

NO

NO

Check U14150

T4 Chip U12101

Bus Activity on

Pins 43, 44?

YES

NO

Replace U12101

(See Note at Top)

Q14302 Emitter

= 5.3Vp-p

Square Wave?

YES

NO

Replace Q14302

Troubleshoot

System

Control

Q14301Collector

= 224Vp-p ?

YES

Q14401 Base

~ 3.1Vp-p?

YES

Q14401

Collector

= 1060 Vp-p?

YES

EEPROM Code

indicates XRP

Fault?

YES

NO

NO

NO

NO

Replace Q14301

With Set OFF is

there Continuity

in T14301?

YES

NO

Check Base Components

Check Bad Q14401, Shorted or open

T14401, Bad Horizontal Yoke Winding.

Check C14403, CR14403 and RegB+.

Horizontal Test

Complete

Replace

T14301

Check XRP Circuitry Q14901, CR14902,

R14902, R14903, R14905

Page 7-6

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CTC203
TROUBLESHOOTING

Vertical Troubleshooting

T4 Chip U12101

Pin 15 ~2.4V

Sawtooth ?

YES

U14501 Pin 1

~2V Parabola ?

YES

U14501

Pin 2 ~ 23V?

YES

NO

NO

NO

T4-Chip

U12101 Pin

26 =7.6V?

YES

T4-Chip

U12101 Pin

20 =7.6V?

YES

Reinitialize EEPROM Vertical

Settings. Replace U12101 if Reinit

doesn't work

NO

NO

Replace RN14501

Troubleshoot Power Supply

Check U14150

Check R14153

U14501

Pin 6 ~ 23V?

YES

NO

U14501

Pin 3 ~ 1.5V?

YES

U14501 Pin 5

~50V Vertical

Ramp?

YES

NO

NO

Check Connection P14501

and Choke Continuity

Check CR14501

Replace U14501

Replace U14501

Page 7-7

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