The Toshiba 43H70 has two RGB driver chips (p/n: STK392-110) responsible for aligning the RGB colors, one of them went bad. Instead of throwing the TV away, I decided to try and replace them, and fix the TV. I did, and it works great!
I ordered two STK392-110?s online from Electronix.com, it cost about $18 including shipping. Each STK392-110 is about 2? in length, and 1.5? in height, and is an 18 pin device. The tools I used were all purchased at Radio Shack, and are: a soldering iron with a stand, solder, de-soldering tool, thermal grease, and a digital camera (yes, a digital camera).
First, make sure the TV is unplugged! On the back of the TV, take the back wooden cover off. You?ll see a bunch of wires going everywhere, a power PCB board (probably brown), and a green PCB system board. The two STK392-110?s are on the green PCB system board attached to two big heatsinks. You will have to remove the green PCB system board to get to the two STK392-110?s and replace them, there?s no way around it.
To remove the system board, you?ll have to remove the board with all the video jacks on it, and will have to disconnect all the wires going to the system board, as well as disconnect the power board from the system board. The power board and system board lie right next to each other, and are connected by two connectors. You have to be careful with those two connectors, and I used a small screwdriver, got it between the mating connector, and gently pried it open. It?s like an old mechanical switch, but instead of one contact, there are several. While taking everything apart, this is wear the digital camera comes in, take a picture of everything you disconnect and remove, and play the pictures backward so you know how and where to put everything back together. The system board is held down by several screws that will need to be removed.
Once the system board is removed, you can see the two STK392-110 driver chips, however, you will have to remove several vertical boards and heatsinks to get to them freely. The STK392-110?s are attached to two heatsinks by two screws each. The heatsinks are soldered on the system board, so you?ll have to desolder them to remove them. Once you have them removed,
Now that the old STK392-110?s are freely accessible, go ahead and use a pair of wire cutters, and cut them off at the leads (the 18 pins). Now desolder the 36 pins left in the board. Use the desoldering tool to get as much solder out of each hole so you can easily put the new STK392-110?s back in. (Make sure you put them in the same way as the old ones!) Put the two STK392-110?s into the holes, put the thermal grease on the metal side of the STK392-110, then attach the heatsinks to them, line up the two mounting screws that hold the STK392-110 to the heatsink, and start soldering everything back together. Make sure you use enough thermal grease between the heatsinks and the STK392-110?s, too much is better than not enough. It will look like the 18 pins are all connected together on the PCB system board, but they are not, make sure you individually solder each of them to the PCB board, and do not let solder from one pin touch solder from the pin next to it!!
Use the digital pictures you took and play them backwards so you can put your TV back together correctly. Attach your TV cable to the TV, plug it in, and use the remote to turn it on (stand back just in case you crossed some wires), it should work, and the picture should be perfect.
Aug 13, 2007 |
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