Burst Capacitor And Cracked Dry Solder Found In Philips CRT TV
This CRT TV belongs to my classmate, who stays nearby my house. When he called me up and told that his TV was dead, I visited his house and checked. Removed the cover and found that the Fuse was blown and there was a bulgy capacitor.
I removed the PCB after observing precautions by discharging the anode to ground. Did a general cleaning and brought the board home for further check up.
Found many of the capacitors had overshot ESR range and become quite old. Looks like this TV belongs to the fag end of 1990s! There were a lot of dry solders and cracked connections.
Got myself involved my extremely enjoying work of replacing all the electrolytic capacitors on this TV and retouching the board from one end to the other. It took several hours of sitting, with healthy breaks not to break my back! Look at the condition of one capacitor and the value of another, which I matched by connecting two capacitors. Since these were in the horizontal section, I did not want to put a 10uF in its place.
Cleaned the board thoroughly and rechecked for any man made mistakes of overlapping solder, causing shorts. Found three of them on minute examination of the PCB under a lens. Rectified these and looked for the jumper wire that goes to the primary of the FBT. The design of this TV was in such a way that when we remove the Horizontal coil connector, it also disconnects the supply to the primary section of the FBT. The Vertical coil connector was separate and that goes to a different socket on the board near the Vertical IC. Just see the pictures below, along with the pictures of the boards after cleaning. This is a very thoughtful and useful design, for making servicing easy. I remembered that in the earlier times, manufacturers provided facilities for board level servicing, but now-a-days, the board replacement servicing methods are employed, increasing the e-waste!
By the way, this TV was having separate modules for SMPS switching and Audio. Just have a look:
The TV was using a very old uController :
Connected a 100W Bulb at the output of B+, which was 95V in this TV and switched on and found the PS working fine.
I had removed and cleaned the voltage adjusting pot from the SMPS switching module. Adjusted it to make it exact 95V.
As the TV was not having a Remote Control, bought a new one from the market and tested. It was not working, though the RC was checked to be working. Checked the IR and found it to be defective and replaced it.
Brought the TV to my home and connected the Board and checked and found it to be working fine!
Here are the parts replaced in this CTV:
Thus added this too to my satisfaction list, with an additional boost when we do something to our own classmate!
This article was prepared for you by Parasuraman Subramanian from India. He is 69 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 repair article below:
https://jestineyong.com/burst-capacitors-found-in-aftron-lcd-tv/
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Albert van Bemmelen
July 30, 2019 at 2:54 pm
Another impressive and professional CRT-TV repair with lots of defective e-caps replaced! You are a real dare-devil by working on those old not epoxy based - mostly paper pressed - printed circuit boards that are an extra risk to fix!
I wonder why you wrote "Since these were in the horizontal section, I did not want to put a 10uF in its place", if they were the ones you found in that position on the TV board.
Parasuraman S
July 30, 2019 at 10:29 pm
It is a 6.8uF capacitor that I replaced with nearest value, connecting two capacitors parallel, to get 6.9uF. Because 6.8uF capacitors are not available in the market. The option is to put 10uF. But that is not advisable in the horizontal section, as value of capacitors are very important in that section.
Robert Calk Jr.
July 30, 2019 at 3:39 pm
Good job, Parasuraman! The rich guys get on TV and beat their chests like Tarzan and then make devices that are difficult to work on. They are a pack of hypocrites!
beh
July 30, 2019 at 8:25 pm
since this tv is older than 30 years I agree with you to replace all the electro caps even without any tests and notice. this action will rescue the machine .90 percent of all problems such as this machine is dried electro caps. thanks, and God bless your arms.
Maarten
August 1, 2019 at 7:53 pm
Actually 25 years, but still a good idea to replace some electrolytics. Good repair!
Andrew
July 31, 2019 at 1:50 am
Hi
I remember that the 6.8uF capacitor was a common fault on this TV but the inductor that supplies the voltage to that capacitor also used to go open circuit causing no line startup to the horizontal stage
The capacitor (6.8uF) forms part of a "kick start" for the line / horizontal stage and once it has it's start up pulse the horizontal oscillator IC takes control
Kind regards Andrew @ VornaTV and Satellite
Parasuraman Subramanian
July 31, 2019 at 10:40 pm
Good tips! Many Thanks!
Tito Kanshulu
August 1, 2019 at 8:35 pm
Thanks for the well articulated article Parasuraman. You have revamped the old tv to new one again by the new capacitors which you have replaced.
Yogesh Panchal
August 1, 2019 at 10:29 pm
Still these TV's are reliable may be works for another 10 Years.
Henrique J. G. Ulbrich
August 4, 2019 at 12:04 am
Very, very good, Parasuraman. The el-caps again! But your patience overcomes any difficulty.
Kunal Pandit
August 29, 2021 at 11:30 pm
thanks for sharing,these repairs of good old electronics gives me a good insight of passive components used during 1990's,i am a big fan of philips's passive components(mkt capacitors,resistors) and audio integrated circuits,along with this i also like japanese components (elna,rubycon,matsuhsita,toshiba,mitsubishi,jrc-njm,sanyo.)i also like the audio equipments from bpl-sanyo.