My 52 My 2nd hand, 52" RCA projection TV will have a great picture for a little while but starts curving until it becomes 3 color lines at the bottom of the screen. It can't be solved by adjusting the colors. It will only start working again after being unplugged for about 3 weeks. Is there a card I can replace?

Need the model number to help as I am not sure of you have a RCA or a Toshiba

You have a problem with convergence and all you may need to do is replace a fuse. Look up convergence for your tv model and hopefully you will get an answer as to where the fuse is located and how to replace it. Very common for RCA tv's

If the entire screen is curved, and it is not taking the whole screen, then you have a vertical deflection problem.

If the colors are double and do not match, with lines of different colors around pictures , then you have a convergence problem, often caused by a faulty convergence board.

The curving effect can be a side effect of bad convergence, or you may have both problems at once.

Unless you are a TV repairer yourself, better calling technical support. Usually you can ring the number listed on the owner manual.

Your model doesnt have convergence ICs. You can get the replacement parts and free instructions on how to do the repair at the following link, just click on the contact us link on the lower left hand side of the website and tell them the model number and chassis they respond quickly.
http://servicemanuals.vstore.ca/

it can be replaced with a t0220 stile case dioded 220k ohm go to nte look up and do a search on the rca part # 259638 search the web for the part.

your set has convergence problems i dont have the answer yet ,i do know that convergence broad is not what is causing this! I have one in my shop now with same problem as soon as i find out problem i will post it !!!!!

are the lines multiple colors? ie; reg, green, blue? If so you need convergence repair, not really something a lay person can do.

This indicates a convergence problem..convergence power supply probally.. however ive seen 2 other cuicits cause this ..

Loss of power supply voltage to run convergence circuit.verify w/service literature.Hands-on technical help needed.

If the screen control for the green picture tube is set too high, then the colors will be greenish, there will be green where there should be black and there will be fine curved lines (retrace lines) in the picture. If you feel confident then you can open the set and look for the focus block which has the 3 focus and 3 screen controls. One row is labeled Screen and the green control will be the center one. Try turning that control down a little and see is the green background and curved lines go away. If they do not go away then there is something more serious wrong. If you do not have experience working on projection sets then allow a qualified tech to handle it for you.