: Hitachi & Other Manufacturers Convergence Problems (STK392-110 ICs) Read Post 1
2010-01-14, 07:38 PM
What an incredible amount of knowledge and suggestions in this thread! Took awhile, but read thru the entire thread. My sincere thanks and appreciation to 57 and all for keeping the info flowing for so many years.
My model is Hitachi 43UWX10B, manufactured in 2001. Developed a red convergence problem. Ordered kit from tvrepairkits.com. Initially replaced both amplifiers (110's) with no improvement, then RK42 and RK46 resistors.
Picture is better but still out of convergence. Tried Magic Focus but only get the static pattern. Pressing Magic Focus a second time brings me back to picture. Accessed the blue button but that does not reset, just cycles me back to picture.
Looked at soldering and board, they appear OK. Also, upplugged the set overnight. I was able to access DCAM prior to the repair, so obviously did something wrong. Any suggestions on where to look/what to check?
Thanks to all in advance.
There's a list of items that people typically do wrong in the first post. For example, changing the ICs and not the resistors can cause the ICs to blow again.
I would have thought you'd be able to access the DCAM via the little blue button though... Make sure not to hold the button down as that can cause a reset - just press and release.
2010-01-15, 12:16 AM
You may have damaged the new ICs... IF you didn't at least check the resistor values to be sure they match the marked value (using the stripe codes). I had a very difficult time identifying the color codes (but I took my digital camera and took close up pictures of each of the resistors and then the color identification was easy). You can locate a resistor color code calculator on the web. Also, on my board, the resistor values were the same regardless of being fully installed into the board vs. one side unsoldered from the board. Recheck the soldering on the back of the board with a good magnifier and bright light to be certain none of the connections are bridged.
Plus, I was told that you must use a digital multimeter when testing these resistors, because most analog multimeters introduce voltage when reading the resistance value and the voltage can cause an incorrect reading. I cannot confirm or deny this, but I did use a digital tool.
2010-01-15, 01:25 PM
I was afraid of the IC damage since I didn't catch the resistors until after putting in the ICs. Still a puzzle on not getting the blue button to access DCAM. Resistor value was provided by tvrepairkits.com. RK 42 = 3.3 and RK 46 = 1.8. I'm off to get a better magnifier and check the soldering one more time. Thanks.
2010-01-15, 07:25 PM
As far as I know there are 6 resistors that have to be checked. On my TV they are indicated as RK42, RK46, RK50, RK54, RK58 & RK62. I would get values for your TV and check each of them (or read the color bands on the existing resistors to decode the proper values). You can get replacement STK394-160s ICs on ebay for $22 per pair shipped (Sanyo parts). Based upon my research, the 160s are superior direct replacement parts for both the 110s and 150s and are recommended by Hitachi engineers. Dont forget to use thermal compound on the contact surfaces AND be certain both mating surfaces are clean and smooth before attaching the new ICs.
I cannot help on the DCAM screen issue, as I have no knowledge there. Good Luck.
2010-01-15, 10:14 PM
Checked and resoldered the ICs and new resistors. Still same problem of no DCAM and some sections of red not converging. Thinking that I may have damaged one of the ICs by missing the resistors initially. I will check the other resistor values but looked at RK 42 and RK 46 because of their impact on red. It was suggested that maybe swapping the ICs may help. Any thoughts? Thanks.
2010-01-15, 11:21 PM
I cannot imagine how swapping ICs would help. If you have a damaged IC, then how would swapping it to a different location help your overall situation? Wouldn't you simply move the problem to a different area?
I am not a TV technician... just another Hitachi owner that had to go thru MEGA research before understanding exactly what requirements needed to be met before making my repair. Luckily for me, my repair went smoothly and was successful.
It is possible there is more wrong with your TV besides for just the ICs and resistors. I do recall reading a post concerning a gentleman who had his board repaired at an Hitachi repair center and the techs did locate some other defective components on that board... I believe a capacitor and something else. Pretty sure it was in this BBS.
At this point, I think you know as much as I do, so my usefullnes is limited.
Again, Good Luck to you.
2010-01-17, 08:58 PM
Swapped the ICs and checked all the resistors (they were OK). Still poor convergence and no DCAM. However....pushed the blue button a second time after it had returned me to the normal picture from the static pattern and it brought me to DCAM. Not sure if resoldering the chips helped any but adjusted the convergence, saved it, and ran magic focus to be sure. All is OK. Thanks for the all the assistance!
2010-01-23, 10:32 AM
OK so I just replaced my IC chips and there wasn't any difference. This was my 1st soldering job so I figured I'd need to do it again. I re-did it and nothing. Did it again and finally a noticable difference. At first my convergence lines were arched really bad. Now I see their straight for the most part but needing a lot of adjustment. The picture is still aweful though. Almost like everything is orangish. When I do the convergence I can not get into 3x3 mode at all. Are the lines supposed to overlay each other and become orange to where you see one line or do you put the red next to the green and blue on ther other side?
Even though the lines are not really curved like before I re did the soldering job I feel like the chips are still not soldered correctly though there was improvement. Is that even possible? I still have a shadow around writing on the screen but it does look better then before.
A proper convergence would have the lines on top of each other to show a perfect white line. Did you replace resistors and check the list of things that people "do wrong" in post 1? When in the convergence screen can you move all of the colours up/down, side/side? If not, then something's still wrong.
2010-01-23, 04:40 PM
OK... now I re-soldered again and was able to converge all colors and lines. The save went through and Magic Focus worked afterword. All shadows are gone but the color is just weird looking now. For some reason everything seems to have a yellow/orange tint. Skin tone looks orange to me no matter how much I adjust the picture settings. I did not have this problem before the IC's went. Any ideas what is wrong now? Thanks for any help.
Did you touch/bump any of the trimpots on the front panel of the TV? What's the make/model of the TV? Trimpots are very sensitive and if moved are very difficult to get back to the correct colour. Of course something else could be wrong with the TV. There are often 6 pots, 3 for colour (trimpots) and 3 for electronic focus.
2010-01-23, 05:45 PM
I messed with the things that twist around which had a white paint on them marking them. I thought that I could possibly fix my picture turning those before I found this forum and realized it was the IC chips. There's a few of them on the bottom of each light and I spun all of them I think. Its a Hitachi 43uwx10b. Any advice?
Even minor adjustments to the trimpots (which you appear to have spun around) throw the colour way off. If you're lucky, putting them back to where they were may get the colour back. This may take an hour or more and a very good eye, if you're lucky. Don't go messin' with stuff if you don't know what it does.
2010-01-24, 09:54 AM
57..... You are the absolute man. Seriously, thanks for your help. The trimpot adjustment made a tremendous difference. I really can't beleive I fixed it since I had never used a soldering iron before.
What are the things under the bulbs that twist. They had white paint marking them and they can really theow the convergence off if messed with?
One final question... Can I change the settings for my Black/white contrast in service mode? Using the user controls does not make much difference and thats the last adjustment I need to get my picture back perfect. As of now its alomost like the brightness is to high but its not the actual brightness control....
The things under the CRTs are probably mechanical focus, or perhaps aiming, but I'm not sure.
Service menu - make sure you read the FAQ in my previous post.
2010-02-01, 01:24 PM
I have (had) the convergence problem described here on my Hitachi. Unfortunately, the TV was used a lot after the problem occured. Some of the posts say this could lead to bigger problems, and it has. The TV now does not display any picture or sound. When the power button is pressed, you can here the relay click and the red light on the front panel comes on but no picture or sound. Can anyone tell me what additional damage may have been done and how to correct it?
This same problem (no pic/sound, not the convergence problem) occured a couple of years ago and it was the video chip. Maybe, by coincidence, that chip went out again? Or, has using the TV with the bad convergence chips done other damage?
Thanks in advance for your help.
2010-02-15, 07:05 PM
Well.. If anyone needs 392-110 STK IC's.. I hope someone will take them off me.
I got screwed big time. I read everything here and it seemed like Hitachi tv's used a stk 392-110 IC... well WRONG!!
I bought the IC's opened the tv and WHAM after removing the heat sink covering the IC's it says STK 4274!!!
Now I have to go out and buy the correct IC's and they won't accept returns.
So, I have these IC's 110's 3 of them sitting in a sealed package untouched... and waste of money.
If anyone needs them, I'll sell them to ya. Otherwise, they are just sitting here and i'm already feeling crappy about getting them and wasting money and time.
2010-02-20, 11:15 AM
I have a Hitachi 43uwx10b that has repeated convergence problem.
First time repair, checked all solder joints, resistors checked, STKs replaced. do the DCAM and convergence is good.
But after a month or so it start loosing the convergence again, I have to do the DCAM to get the convergence back.
Have you ever see a problem in the loosing convergence data?
If the ICs go, the convergence usually goes altogether and cannot be adjusted in the DCAM. You may have something else that's causing the drift - resistors, capacitor? If it drifts again a lot, then it may be a sign of something else going - looks like you didn't change the resistors as recommended for example...
A small amount of drift is to be expected, but not a huge amount. I used to adjust my DCAM every 6-9 months because of a small amount of drift, usually near the edges of the screen.