Hello, I have a problem with my tv witch only produces sound but no picture,,, It sometimes comes on displaying only one white horizontal line right in the middle and nothing else. Does anybody have any ideas or is this unit done. Thanks much.
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Re: Black screen with sound only no picture.
Horizontal line displaying means that fly-back transformer is working, only the picture collapsed. Check high tension voltages around 20-25kv (be careful of the high voltages, don't test with the ordinary AVO meter/tester, high voltage meter could be used for the high voltage measurements). Check dry joints around the horizontal section which can cause the picture collapse. Re-solder the dry joints, it will fix the problem.
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Hello jreese, Hi, Most definitely its a horizontal output problem, your tv has no horizontal deflection to pull the screen vertically, the power transistor that produces the high voltage is bad, this needs to be replaced. definitely you always have sound, the audio section is a separate block from the high voltage block, go look for a technician to have this checked.
If you wish to get some details; visit the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.
Search the site by type in the "BRAND NAME" of your device; (Exclude the model number), in the "Search box at the top right of the display window of the Homepage" to get gathered related posts
From your description it sounds like a bad picture tube. The lines are called retrace lines. There is a small chance that a component on the small board that connects to the neck of the tube may be bad. Without model number information it is very difficult so say further. Some picture tubes can be re-jeuvenated with the appropriate machine ( at a TV repar shop)
If you feel adventurous and are careful you might try GENTLY tapping the neck of the tube and see if picture improves/goes out. If the tapping does change the picture it is definitely the tube
Middle going across the screen from left to right??
This unit is plagued with bad solder connections in the comb filter board and flatpack underneath the comb filter board. These connections can cause any odd number of problems in video display. If it is that it's not expensive - virtually no parts. If it's a single line across the screen could also be the vertical circuit involved.
My suggestion is to have it estimated at a reputable shop and take it to them rather than the more expensive pu/del charges.
If you would like go to http://www.nesda.com/locator/state_search.php and locate a servicer from there. Kinda like going to the AMA to find a doctor...
Hope this helps!
You need to consider the following tips herein as follow:
1) Field collapse (horizontal white line on screen) R710 dry joints. Same as C2146TN & C2546TN problem solved with thanks to Mike G & Barty. Power off/unplug. Get to circuit board underside with aerial socket up-R710 is near top and right of centre-cluster of 4 joints best resoldered
2) Picture is horizontally narrowed and deformed Capacitor C2913 (390nF, 250V) on the deflector PCB had lost capacity