I have this tv, which is mitsubishi make and a cathode ray tv. it has been working fine,but since 1 month ago the tv does a wierd thing. once u switch it on,its fine but after like 2mts the tv screen display shrinks to the centre of the screen.so all u see is a 10cm wide line of display stretching through the centre of the screen. How can i fix this my self.please help...
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Re: tv screen shrinks
The first solution is correct , but there are a few missing facts, in order do do the repair correctly you must replace the vertical output ic (TA8427k) and all the capacitors that surround the heat sink and the vertical ouput IC. be sure to coat the heat
sink with heat sink compound.Also the current limiting resistor off the IHVT sometimes opens or
changes value. If you do all these thing and upgrade the capacitors from 85 Degrees cent to 105
centigrade., the problem will not raise its ugly head again. Also due to the poor Q>C of replacement parts , it might be nec. to go into the servicemans menu to re-align linearity and center. Scrivitron
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Re: tv screen shrinks
Looks like some of the Electrolytic Capacitors in the Vertical Output stages have dried out and need to be replaced. If you are conversant with Solid State electronics servicing, then you can make an attempt.
I generally do not waste time identifying the faulty capacitor, but replace the entire lot in thre Vertical stages. There are not more than 8-10 of them. Since you are changing them en masse, should not take you more than 30 - 45 mins to desolder the suspect ones, and solder the new ones. And it also saves you the bother of new problems cropping up in the near future, as all potential problems with old capacitors get removed.
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The color signal consists of Red, Green and Blue. Those three colors, at various degrees, make all the other colors on your screen.
If you have a BRIGHT green screen it's best you don't operate your set. If it's just tinted green then there is a problem on the CRT (Cathode Ray Tube) drive board. Do check your "tint" setting and see if someone misadjusted it. If that isn't it then you need to have your set on an electronics bench and get an estimate for repair.
old tvs CRTs ( cathode ray tubes) pick up signal better than LCDs
So yes good quality satellite cable with better screening and low loss cable will be better, plus a new aeriel may do the trick.
Is your tuner in new LCD faulty though,? try it on your friends tv where you know the signal is fine.
I realized that there is a 90 day warrantee on parts and a 30 day limited warrantee on labor for the repairs that were done. As I stated, the original problem was the picture shrinking after a few minutes of the set being on. The repair firm took my control board with them. When they came back to install the repaired control board in my set there was a load spark during the installation, after which I had a black screen and no sound. The repair firm took my set them and installed a "CAP Kit", a STRM6511, and a "D1881". The set worked perfectly until two days ago.
I called the repair firm an they are coming out this Thursday to check out my TV. I am hoping the problem is related to the failure of one of the parts installed to fix a similar problem which occurred after the sparking incident.
I would check the green signal all the wat to the display screen to determine is this is a signal problem or a system short. I would recommend that you take this set to a qualified electronics technician
If you feel up to it, there is probably a potmeter inside that you could try to adjust. I tried this on a TV a long time ago.
You should know, though, that there are thousands of volts in some capacitors in there (so I've been told) that might shock you if you're not careful. *Even if the TV has been unplugged!* The capacitors store power and are not automatically discharged when the TV is unplugged.
It's the parts on the cathode ray tube that are (most) dangerous, so don't poke around with your fingers or a metal object.
I would probably leave this one to a qualified technecian, though.
If you do open it and fix it, make sure to get all the dust in there out while you're at it to prevent any fires later. Your TV will have collected a lot of dust.