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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You may check on his previous article on Jumping Of Pictures Solved In Panasonic LED TV Model TH-32D200DX