Zenith TV - Model SM3547RK- Distorted Wide Picture

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stelios
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Zenith TV - Model SM3547RK- Distorted Wide Picture

I have this 1994-vintage 35" Zenith TV - Model SM3547RK. Recently while watching TV, the picture (video) went totally black. The sound (audio) continued to work. I had a TV technician analyze it. He removed (one of) the circuit boards inside the back end of the unit (right behind the tube/CRT). He took it to the LG depot (in Canada) and ordered a replacement board (that was shipped from Mexico supposedly). He installed the board, the picture came back but it was severely distorted. He attempted to calibrate it using a plastic screwdriver I believe - no luck. He did not want to force it because it is a mechanism that can break easily (he said). He suggested that he get another board in case we had better luck with the calibration mechanism with another board. The board arrived, he installed/connected it but with the same results. I have a picture but it is very distorted (objects are oversized and spill off the viewable screen both vertically and horizontally). He could not calibrate it again. So he gave up. Now it so happens to be a TV that has a sentimental value (bought by my father 12 years ago) and I believe that a person with the proper skills can find the cause of this problem and get it back to good health. It is a beautiful set and has provided many years of good service. Any suggestions on how to proceed? He suggested that maybe the tube/CRT's external electronics are blocking the proper calibration and a techie friend suggested a failing power transformer. Any suggestions? Thank you in advance.

Larry Dillon
Larry Dillon's picture
It sounds a though there is a

It sounds a though there is a problem in the sweep correction circuit.  The circuit that drives the deflection yolk, most likely as simple as a bad capacitor.  This is not a repair a user should attempt without have some experience in TV repair.  This is part of the high voltage circuit. Maybe call in another shop to have a go at it.  I am sorry the set is sentimental, but I am afraid this set is going to cost big bucks to have it repaired correctly.  I have seen folks in the past get a big nice wood cabinet with a worn out TV set, and have a repair and wood worker install another set in the place of the old  screen.  Just a thought. if you really wanted to keep the cabinet. Electronics will wear out after awhile.  Good Luck, and let us know how this turned out.

stelios
stelios's picture
I brought in another TV tech

I brought in another TV tech who spent 90 minutes checking all the components (capacitors, etc) on the board with his meter. He replaced a couple of them and managed (with much effort) to calibrate it almost to its original precision. Cost: $129 USD.

Larry: thank you for your suggestions. I showed your comments to the tech before he started his repairs.

Larry Dillon
Larry Dillon's picture
stelios, Glad to hear you had

stelios, Glad to hear you had someone else look at the set.  You got extremly lucky to find a good repairman.   I would hold on to the name, and recommend him to anyone who ask, as a good honest tech is hard to find these days.

 

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