Intermittent On/Off Problem In VIDEOCON CRT TV CTV22NP Solved
This CRT TV was brought to me with the complaint that it is intermittent in getting on. The set was handled by some technician before. The customer wanted this to be restored as he wished to gift it to one poor man. While thankfully acknowledging his gesture, I requested him to help me clean the inside very well and transfer the heavy TV to a table inside. In order not to get back the low back pain problems, I am very cautious in taking help of the customers, about which I tell them when they call to report a complaint.
On bringing the board to my service table for inspection of the condition, I quickly noticed several dry solders, one of which is shown below:
When I checked the ESR of caps, most of these were out. So, went ahead and replaced all the electrolytic caps on the main board and CRT PCB. Here you can have a look at the board with caps inserted in place, before soldering and cutting.
After finishing this work, I retouched all the points on the board from one end to other. Just take a look to know how clean the PCB was after retouch of solder and thorough cleaning.
Then when I switched on, it did not get on! Voltages were ok. But it was not starting oscillation. Though I tried all my known tricks to locate the fault, I could not succeed. All stages were showing the correct voltages. I repeated my troubleshooting for days without any result. Once in a while, I looked into and sometimes the TV worked and many times it did not, i.e, back to square one.
When I almost lost hope and proposed a replacement of the board, one of my techie friends came home to pick up a panel damaged LED TV, which he bought from me. As per my request, he spent some time in troubleshooting and finally located a pin of uController IC, which was not properly inserted (probably by the previous technician, who had removed this IC for some reasons). So, it was making and breaking contact. But one cannot make it out from the bottom. It was only due to his professionalism this could be traced.
Anyhow, he removed the IC and put it back. That’s all! The TV got on and worked very well for several hours, bringing relief to me! I paid his charges, though he declined to take it. So, curtain fell on this long pending issue.
Satisfaction, with the accrued interest got collected with a big relief!
This article was prepared for you by Parasuraman Subramanian from India. He is 72 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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Charles
November 5, 2022 at 10:01 am
Congratulations for yet anotheraccomplishment in saving this CRT and thanks for sharing your knowledge as well as your techie friend skills.
Parasuraman S
November 5, 2022 at 9:32 pm
Many thanks for your support and encouragement!
Mike retz
November 5, 2022 at 12:40 pm
Great story. Thank you. Int. Connections are troublesome. Temp. And humidity play a role. When I w orked rca service company. Chicago I did service calls. Common trouble was picture comes on sometimes then goes out! Sometimes works all the time! Problem was traced to a soldier connection in the tube filament circuit. The chassis was used to make connection to circuit board by way of a stake grommet on the circuit board. These were disimilar metals and would conduct when temp. Was just right causing the filaments of the 6gu7 tube to go dark! Crazy problem. Solution was to take a Weller 325 watt soldier gun and heat and apply flux till shiny. RCA finally issued a bulletin to correct proublem. Thanks for all your articles. Your the man!! ✌✌✌
Parasuraman S
November 5, 2022 at 9:34 pm
That was a lovely share of your experience! Many thanks for your support and encouragement!
Tayo
November 5, 2022 at 1:15 pm
Timely article! I suspect an ill-seated IC is causing an intermittent problem on one of my smart battery chargers. Thank you for this article!
Parasuraman S
November 5, 2022 at 9:34 pm
Many thanks for your support and encouragement!
Albert van Bemmelen
November 5, 2022 at 2:07 pm
After reading about this painstakingly long timeconsuming repair I am very glad that you completely managed to get this old tv working again! And I feel with you the caution not to get back low back pain problems. As I myself being almost 2 meters tall suffered from those in the past every second of the day for many years! Mostly caused by bad jobs with wrong working conditions. Those jobs also caused heavy migraines about every 2 months because of neck problems why I went to see a great chiropractor who helpt me to get rid of most of my health problems. And he also advised to buy a thick mattress to help to relieve lower backpains. Now since 3 years I have the healthiest job in the world as maildelivery guy on a bicycle. And my backpains and migraines are good as gone! Coming back to your article I think it is a good idea if you start with replacing all capacitors only AFTER you know the device is working!
Parasuraman S
November 5, 2022 at 9:36 pm
Many thanks for your support and encouragement and specially for your expert advice! Very glad to note that you are hale and healthy and cycling all around! Great!
Yogesh Panchal
November 8, 2022 at 6:44 pm
Sir,
"Give time to Heal" Sometime sentence is perfectly fit to these type of situation .When we tired on troubleshooting & leave the job for some another day you will fix the equipment in unexpected early time frame.
Parasuraman S
November 8, 2022 at 9:50 pm
Well, that is a very nice and accurate statement from experience! Many thanks for your comments!