I REPLACED CONVERGENCE IC'S ON LARGE HEAT SINK , REPLACED STR F6628 DUE SHORTING ACCIDENT . STILL NOT TURNING ON. I JUST READ ABOUT THE 2 FUSES ON A SIMILAR QUESTION . GAINING ACCESS FROM FRONT FOR THOSE , ARE THEY MARKED ? ANY INFO IS HELPFUL !
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If one of the two stk-392-570 chips has shorted it will blow a pico fuse on middle board and set will not come on.
Plug set in, turn on, when green power light goes out on the front of the set press and hold both the menu and input (device) buttons for at least five seconds and release both.
Power light will blink a two digit error code: if 2,2 it is a blown pico fuse and the chips also must be replaced. I have start to finish step by step instructions that are available if the customer selects me to answer in the new Marketplace here on Fixya.
see attached photo of chip and also part of middle board with the green pico fuses.
chips look like this but will have 570 number on them.
Most of the time there are one or more 5 amp pico fuses open on the power supply. The cause of them opening is the +/- 30 volt line shorting from the convergence circuit. If you take this repair on yourself and are familiar with a ohm meter, you can check the small green pico fuses in the power supply. Remove the power from the set, take the back off. The board in the center is the power supply and convergence circuit. In the center of the you will a transformer. Just to the left of the transformer you will small green fuses that look like resisters. They are marked on the board but are sometimes hard to see. If one is open for the 30 volt line, the convergence IC's need to be replaced. They are mounted on the back of the large heat sink and the board must be removed to replace them. When you remove the board, be sure to remove all the screws not only around the edges of the board but also in the center too. There are also screws on each end of the heat sink and on the blind side center foot securing a ground wire. On each side of the board there are plug clips that must be lifted. At the front of the board there are plug connectors that need to be unplugged. Once the board is removed the IC's are easy to replace. Remove them from the heat sink, Unsolder them from the board using solderwik. The Convergence IC's should be STK392-570. If there is only one, it is a STK393-110. When replacing them, I recommend using heat sink compound on the back of the IC's where they contact the heat sink. solder in the new IC's then attach the heat sink to them.
Replace the small pico fuse or fuses, they should be rated at 5 amps. Once all the parts are replaced, remount the board making sure the heat sink holes align with the board holes. Reconnect the plug connectors, Plug clips, and reinstall all the board screws.
You need to be concerned about the convergence board. This is the board with all the RCA jacks and RF connections. Pull this board out. You will see two very large cooling fins [heat sinks] with two large ICs [black with about 15 pins each. Marked with #392 ---] I don't know the exact# right now. Replace these Ics. And check the small resistors that stand tall next to theses Ics, replace if necessary! Let me know what you find.Thanks for asking me!
Your symptoms sounds like at least one damaged convergence IC.
You are correct you can sometimes rework the solder connections on each of these IC’s, although, if the convergence does not fix itself from time to time, you most likely do not have a bad solder connection. You will have a faulty IC. I recommend to replace them both at the same time because the chips legs can fall off due to the heat of the IC. Please be sure to remove all of the white heat sink compound on the heat sink and apply a even coating over the back of the new IC’s. You should also bolt them down before you solder them in so that you have them at the correct height. There are two and sometimes three very large IC’s that control the convergence in a big screen set. I believe that your set has two. They are secured to a very large aluminum heat sink. I think that the IC numbers will be IC8001, 80002.
The IC’s are large and black, you cannot miss them. They will usually have an STK-XXX number on them.
There are several schools of thought on the replacement of parts and I firmly believe that you get what you pay for, so don’t buy the cheapest IC’s that you can find. One company I worked for tried this and it only caused more work for the technicians, as we had to replace them with the more expensive ones in the end. I would think that you should be able to find these for around $60.00 each. If you can find the exact Mitsubishi part, even though the numbers on the front are the same, and they look exactly like the $10,00 ones, they are better and more reliable. I hope this information allows you to resolve this issue. If I have helped you, please help me, and rate this suggestion the highest FixYa rating. (Two Thumbs Up) Please Note: If you can not rate this post with the highest rating, then please do not leave any rating. I am doing this for free and I do not think that any rating other that the best is needed. If you need further assistance please comment to this post and I will try to help you further.
Yes, you have a convergence problem.From what you say it sounds like the Convergence IC's have failed. Part number 267P150010, STK392-570, replace both IC's. They are on the middle board secured to a large heat sink. Good Luck, big IRISH.
Whoever told you that the WT46809 took two STK392-570 Ic for convergence amps were absolutely - 100% correct... The amps are located at position number Ic8c01 & Ic8c02 on the board. Very difficult to miss too they are about half the size of a pack of cigarettes and 1/4 as thick. They are Mitsubishi part number 267p150010 and after replacing them you want to also check all the low ohm resistors in that circuit for the yoke return.
If you order them don't get them from ebay or some other less than ignorant place, our industry is loaded with chineese knock-offs that would last tem minutes in your set before failing again... Personally I'd order them from Acme Enterprises out of Florida, 800-575-9833 and know that they were Sanyo originals that way.
BTW: If you replace these yourself make sure to use a generous portion of heat sink compound on the new installs for heat dissipation.
No. Usual procedure== Check the IC's that are mounted to the large heat sink on center circuit board.Part # Stk392-570 X 2. Check fuses FA904 & FA905 in power supply-replace,if open. If either fuse is bad, replace both convergence IC's. If both fuses check good and both IC's check good with your meter,then check all the other fuse devices in power supply. After that, advanced diagnosis by an experienced TV tech might be needed.
The convergence IC's are black in color with white lettering on them and will start with STK. These IC's will be standing up and be about 2" X3" in diameter. These IC's will also be mounted up against a large metal device called a heat sink. good Luck