The lines are retrace lines and the green screen could be a problem with the picture tube or a problem with the video circuitry connected to the green gun of the picture tube. Troubleshooting must be done to determine the overall cause of this problem. Is it an easy fix. If I were in my shop and you bought this set in, it would be finished in a day. It being easy depends on the person, easy for me may not be easy for you, I have the equipment to fix this problem, and that is what it will take. let me explain:
First I would use a schematic to show me the voltages that should be present on the picture tube socket board, for red green and blue.
Then I would measure the high voltage on the anode and write it down (usually 20Kv to 30Kv)
Then I would inject an known good signal into the TV (usually color bars) via the RF input on channel 3
From there I would make sure I write all of my measurements down and compare them to the schematic.
At this point I would waant to make sure the picture tube could not be the culprit, I would power off the set unplug the set and then discharge the high voltage anode of the picture tube I have a tool that does this but it can be done with a big flathead screwdriver and a clip lead.
Attach the cliplead to the screwdrive and then the other end of the screwdriver to ground.
MAKE SURE THE SET IS POWERED OFF AND UNPLUGGED!!
Manuver the flat blade of the screwdriver under the rubber cap of the anode connection on the top of the picture tube and make contact with the metallic clip (you may draw an arc so be prepared for an electrical discharge).
Once you do that leave the screwdriver inplace as you remove the rubber cap and the metallic clip from the anode of the picture tube.
Once this is done, remove the socket board from the back of the picture tube. At this point you will now use what is called a CRT Analyzer/Rejuvenator.
Follow the setup and test instructions for the CRT Analyzer/Rejuvenator perform a tube check first and if the tube shows bad on any of the guns, perform a rejunvenation run on all threen guns, balance them and then test them again (repeat this about four times if needed), an more and you can count the picture tube as bad.
If the tube is good or can be bought to a good state then reconnect the anode and socket board and reapply power.
If the problem is gone then it was the tube, if not then it's the circuitry and then troubleshooting is needed, to find the problem in the video circuit.
I hope this helps.
Apr 29, 2007 |
Sanyo DS27910 27" TV