20 inch TRC TV repaired
I went to my friend’s house for a visit and he asked me to take a look at his old TV which was not working properly. It was an old 20 inches TRC TV-VHF/UHF brand ELTEC Model CT-2021, Japan made TV.
He told me this TV set already worked for more than 20 years and this was the first time it had problem. My first thought was, if the ELTEC engineer knew about this they would be glad to have designed such a good TV.
As you can see from the above pictures it seems that there was a visual malfunction. The device was disarmed, an easy job; only some screws.
As you can see in the photos above there was a great amount of dust inside the equipment. The PCB was fully extracted for servicing.
The worst part I saw in the PCB was the circuitry around the STR50103 IC (Voltage Regulator) because there were many cold solder joints.
The IC was re-soldered together with all the corresponding components. The device was connected back into the AC-mains and when it was turned on, the picture was in perfect condition. The device was cleaned too with air pressure.
I gave him an advice to take out the rear plastic cover and put the TV set in the garden of his house to take a sun bath for some hours (it’s a traditional method in my country) Why? Because a lot of humidity was seen in the TRC and in the PCB too. Some people use Hair Dryer, but I prefer the sun bath: it’s a natural source of heat. Another old model saved from the dump.
This article was prepared for you by Humberto Rodriguez, one of our ‘Master Authors’ from Cuba.
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gcharal
May 6, 2015 at 10:28 pm
Good repair!!!
Can you tell us what was the cause of humidity?
I observed humidity in a tv-set that i repaired last year
but i can not explain what was the cause.
Keep on the good job.
Save the planet!
George from Greece
Albert
May 6, 2015 at 11:31 pm
Hi Humberto,
Repair is one thing, but cleaning a twenty year old dusty tv is something that is not a nice job. Sadly we can't leave the cleaning to the customer. I also use a compressor (13 euro for 1 dm3/liter for the special compressor oil, because not oil free use) if I occasionally need to clean stuff, like personal computers and so on, but I always wait for a good sunny day to do this outside (and they are rather short in Holland. We can have all types of season in one day).
I've got some old tv's here too, 6 or 7, and some crt-monitors but nobody wants them. Not even for free! And the main thing is that here in the Netherlands you can't recieve any programs on them anymore with the beginning of DVB-T transmission (Digital tv).
I take it that in Cuba the tv signals are unchanged as they were decades earlier? The only way to watch tv in our country on old tv's is to transmit it yourself at home with your own analog transmitter.
By reverse engineering I've made a schematic of an UHF color tv transmitter that I already build several times. If you want it I can send the DIY information to you so you can build one yourself?
With a Yagi antenna you can transmit over longer distances, but with a normal wire antenne about 50 to 100 meters.
The hard part is making the little audio transformer coil. The 4 transistors are not expensive and shouldn't be hard to get?
And 12 Volt, and a videosignal from DVD or VCR is all you need.
Greetings,
Albert.
Rey
May 8, 2015 at 2:13 am
Albert, goede middag. Do you mind to send me a copy of the schematics with parts list? It looks like an interesting project to build. I would appreciate it.
Dank u wel
Thank you,
Rey
Robert Calk
May 7, 2015 at 1:24 am
Good job Humberto.
Bernie Scott
May 7, 2015 at 1:45 am
Great job......I have an old RCA floor model color tv here that was made in the 1980's aside from having a weak picture tube it works great....that cannot be said about modern day electronics......and it is very sad indeed as most shops will just write the stuff off and throw it out.....it is too bad there is no market for used electronic components....keep up the great work.....
Cheers,
Bernie
Andre Gopee
May 7, 2015 at 7:28 am
Great Job Humberto... A perfectly Good Set would of been wasted if you did not take a look at it. Keep up the good work.
reza
May 7, 2015 at 9:19 pm
hi
thank u for share this article
Albert Hoekman
May 8, 2015 at 5:13 am
Nice job Humberto
aziz
May 8, 2015 at 7:21 pm
hi mr. jestine yong your website is very good. thank you i am from Afghanistan
Jestine Yong
May 8, 2015 at 8:32 pm
Hi Aziz,
You are welcome.
Jestine
Florin
May 10, 2015 at 6:58 pm
You can't get so much humidity in a TV unless a flower vase/pot sit ON the TV and it was bumped over spilling water inside. I saw that many times because women think a TV is not looking pretty enough...