TOSHIBA projection television Model 50H12

This is what you need.
TOSHIBA Convergence Repair Kit CRK-23735096 50H12 50H71 50H81 50HX81

The only way to get this fix, is replacing the defectives convergence IC's.

OK, the problem is one of the STK392-110 convergence amps has died. It is rare that both die at the same time, so either vertical or horizontal will go out, but not both. Also look for an open fusable resistor near said IC.

The convergence ICs and the six 1.8 ohm 1watt resistors need to be replaced. You can get the convergence repair kit for your model at www.tvrepairworld.com which has the Two Convergence ICs and the six resistors plus the CD with instructions on how to do the repair.

See my solution <http://www.fixya.com/support/t2795690-convergence_off_blue_line_only_vertical>.
You need to get to the service menu--it's been 4 years so go to AVSforum.com to turn off the different guns and get the better pattern.
At your risk: To get into Service mode:
1. Turn your TV on. 2. For X81 or earlier series: Press MUTE on your remote and release. 2. For H80/H81/HX81 series: Press MUTE on your remote and release two times ("Mute" on-screen) 3. Press down MUTE on your remote again and hold. While holding, press the MENU button on your TV set's front panel. 4. Release both buttons. 5. An "S" should appear on your screen. Press MENU again on your TV. 6. Now you're in service mode. Channel Up/Dn - Scrolls through Parameters and Volume Up/Dn - Changes Parameter Value
To get into convergence mode:
Get into Service mode, then Hit '7' to bring up the convergence grid. Buttons 100, 0, and ENT control which gun you want to turn off (if you want to align the red to the green without seeing the blue gun and other variations). 2=up, 8=down, 4=left, 6=right, 3=change gun to converge, 5=converge that point. To exit convergence mode you press 7 once and your screen should look like it's imploding then return to normal and then you press 7 to get back into regular service mode.
I have more info found on the board. -Ken

Often convergence issues do not require the entire board to be replaced. You can resolve it by replacing the convergence ICs. The part in question is STK392-110. You will need two of them and they cost around 10$ each. But replacing them is a pretty complicated procedure and I would not suggest it to someone without prior experience. A service manual should get you started in the right direction if you are planning to do this yourself.
https://www.completeservicemanuals.com/toshiba/crt-projection-television/57h81-service-manual/prod_1128.html

PS: Disconnect from the power supply before you start the repair. Also read the legend, the hv circuits are denoted by a special symbol, so you will know what you shouldn't touch.

You may also need to replace the nearby resistors that may have popped the IC in the first place. Read the service manual for further details.

Good luck,
Sai.

you can get the convergence repair kit for your model that has both convergence IC and the six feed resistors at this link, The repair kit also has step by step instructions with pictures so you can do the repair your self. Heres the link.The 50H82 kit is the same for the 57H82, http://servicemanuals.vstore.ca/product_info.php/pName/toshiba-50h71--50h81-convergence-repair-kit/cName/convergence-repair-kits

your convergence IC's are bad, it is 2 3 inch chips that have to be soldered onto a board in the back, after you unsolder the old ones,they cost about 40 $ for both

The convergence IC`s need to be replaced and the related low ohm resistors need to be checked for proper value.

O.K. This is a CRT Projection TV see http://www.tacp.toshiba.com/televisions/product.asp?model=50H82 The Manual is available from http://www.tacp.toshiba.com/tacpassets-images/models/50H82/docs/50H82_om_e.pdf , and this describes the Manual Convergence process, I doubt this will help, but it's step #1. The problem you are describing sound to me like a deflection problem. The electron beam in the green projection 'tube' (a super bright CRT) is probably not being controlled correctly. This can be caused by several things, from least likely to most :) I do not recommend that someone untrained in electronics attempt to service a CRT based television due to the potential for extreme shock or electrocution. That caveat said, here are the possibilities. #1 Physical Trauma: The TV has been shifted moved or bumped hard, and one or more of the fixed permanent magnets used to help convergence has come loose, or the CRT projection tube was damaged. I don't think these TVs use convergence magnets anymore, but it's possible. The green CRT tube failing would be more likely if all four corners were affected, but I've seen a failing CRT affect a single corner/edge before. I believe that this model has projection tubes that are separate from the colored filters, so swapping the tubes around may be possible. I do not have a service manual for this set, and this may be a hazardous operation due to high voltages. #2 Stray magnetic field: Someone dropped a magnet into the TV, and it landed close enough to the green tube to effect it only, or perhaps some other piece of equipment is effecting JUST the Green CRT (clock radio, speaker, badly designed wall wart, etc.). Removing the offending magnetic field may cure the problem. Perhaps the offending magnetic field has been removed, but it's presence is still felt. Try using the degauss function built into the TV set (I can't find one in the manual, but it may be present). You may want to try using a degaussing coil, and see if that helps the problem. Just be careful not to get the coil too close to the base of the projector tubes. #3 Deflection drive electronics: A CRT works by using an electron beam to excite fluorescent compounds on the face of the CRT. To move the electron beam about, a process called deflection is employed. Magnetic coils (the choke) are used to steer the electron beam up, down, left or right. These coils are driven by transistors, and as one fails, you will get an image that starts collapsing in the affected section. On a standard CRT TV, that would mean the entire image is affected, but a CRT projection display uses separate red, green, and blue CRT projection tubes to build the image, so you have three times the deflection, three times the possible transistor failures, and in your case, the odd result of just the green part of the image displaying incorrectly. This problem will probably require a service call, and a electronic board swap, but the problem could be the choke (the magnetic coils) on the green CRT projection tube. Swapping the green tube for another tube could prove if it's the tube or if the deflection electronics that are going out. Again, my feeling is that this is a deflection issue requiring a board swap (I doubt anyone actually does component level repair anymore) Sorry, I don't have a better answer, peace. Paul.