Video Missing In Samsung CRT Solved
Model and make : Samsung CB20-F4 CRT TV
Problem reported: No video, audio ok. (Black screen).
Checking at workshop: Problem confirmed.
Trouble shooting and rectification done: Retouched uController IC and Chroma Processor IC and a few other places wherever it was found. Power supply was not stable. Traced it to 120K Resistor in SMPS. Replaced it along with a couple of high voltage capacitors. As Horizontal Oscillation was taking place and all other voltages on the board are ok, suspected the TV Processor IC. Replaced it. Video came on with blur raster. Checked the Focus Voltage Wire inside the CRT Socket and found it to be worn out due to fungus attack. Cut the tip and made a fresh exposed contact and soldered it. Also replaced screen voltage filter capacitor as a routine preventive maintenance. Saw the menu was not clear enough and looked like the settings got affected, indicating a software corruption in memory IC. So replaced it with a blank memory IC. Switched on the set and allowed the program to do the auto copying to the blank IC.
Result: Fed Video and found it to be working very well. Mission accomplished, adding one more satisfaction to the collection bag.
Here are the pictures:
This article was prepared for you by Parasuraman Subramanian from India. He is 70 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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