Text preview for : TFC-04051_CTC211_Scan_Loss_Troubleshooting.pdf part of RCA D52130 Large File 6 pare RAR Folder containing: Flow Charts, Tech Tips, Trouble Shooting Manuals, Updates, Module Training, and Symptom Fixes
Back to : RCA_CTC210-211_01.rar | Home
THOMSON TECHNICAL COMMUNICATION
Television
Troubleshooting Flow Chart
TFC-04051
The information contained herein is provided solely to assist qualified Technician in the diagnosis of the problem described. It is not intended as a modification or alteration of the product.
REVISION DATE: Chassis: CTC211 9/23/2004
TOPIC: Scan Loss Troubleshooting SYMPTOM: No Video - Pulsing
Warning!
To perform the troubleshooting in this flowchart, it will be necessary to defeat a safety circuit (scan loss). Make sure the CRT (s) are disconnected before attempting this procedure. Remember to restore all connections or components to normal condition before returning to the customer.
Short Q14105 between base and emitter. Apply AC. This should force on the run power supply.
1
1A
Are the Chassis fans running?
No
Troubleshoot the Run Power Supply.
Yes
Go to page two
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 1 of 3
THOMSON INC.
CTC211 Scan Loss Troubleshooting cont.
2
2A
Is the high voltage operational?
No
Go to the High Voltage Troubleshooting F l o w c h a r t T F C - 0 4 0 4 9.
Yes 3 3A
Locate Pin 3 of U13101. Press the power button. Is the 5vdc missing?
No
Go to System Control Component Level Troubleshooting F l o w c h a r t T F C - 0 4 0 5 6.
Yes 4 4A Troubleshoot the Horizontal Scan B+ power supply or check U14104 in the run power supply.
Remove AC and desolder pin 18 of J14102 (Hor. SIP plug). Reapply AC. Does pin 3 of U13101 rise to 5VDC?
No
Yes 5A Check VCC at pin 16 (12VDC) of J14102. If missing, check U14104. If the voltage is present, suspect a Data/Clock problem going to the Horizontal SIP board or the SIP board itself.
5 Remove AC and desolder Q14451 Coll. Reapply AC and press the power button. Is the Horizontal drive present at pin 15 of J14102?
No
Yes
Go to Page Three
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 2 of 3
THOMSON INC.
CTC211 Scan Loss Troubleshooting cont.
6 Steady Pulsing
Is the horizontal pulsing off and on or steady?
7 7A
7B
Resolder Q14451 and turn on the unit. Check for Flyback pulse at pin 7 of U14102. Is this waveform present?
No
Go to the Horizontal Troubleshooting Flowchart T F C - 0 4 0 5 0.
Go to System Control Component Level Troubleshooting Flowchart TFC-04056
Yes 8 8A Remove AC and reconnect pin 18 of J14102. Apply AC and press the power button. Check pin 18 of J14102 for 5VDC. If the voltage is present, scan loss is operational. If the voltage is missing, suspect the Scan B+ circuitry or the Horizontal SIP board
The Waveform should be 40VPP. Is it low or missing?
No
Yes 9 9A Measure the collector of Q14904 (19VDC). Is this voltage present? Check Q14706 (12VDC sense) for leaky or shorted state. Also check Q14903 and Q14902 for leakage. If these test ok, check Q14904, CR14902, and R14909 for the problem.
No
10 The XRP and 12VDC sense Scan Loss circuitry is functional.
Product Safety Information
Product Safety information is contained in the appropriate Thomson Service Data covering models/chassis referenced herein. All specified Product Safety requirements and testing shall be complied with prior to returning equipment to the customer. Servicers who defeat safety features or fail to perform safety checks may be liable for any resulting damages and may expose themselves and others to possible injury.
First Edition First Printing Copyright 2003 Thomson multimedia Inc. Printed in U.S.A. Trademark(s) ® Registered Marca(s) Registrada(s)
Page 3 of 3
THOMSON INC.