: Hitachi & Other Manufacturers Convergence Problems (STK392-110 ICs) Read Post 1
2007-08-11, 01:49 AM
This forum has been extremely helpful and particularly this thread helped me pinpoint the problem of convergence when our TV - Hitachi 51SWX20B acted up last week. Thank you to everyone and especially to all the voluntary moderators.
I changed the ICs - STK392-150 and the resistors as mentioned and after double checking the connections/ pins etc. I cranked up the TV. It ran well for about 2-3 minutes and was even able to run magic focus via remote and the picture came back. But then all of a sudden the convergence problem came back and the TV shut down on its own. It continues to do so when powered up.
All the time that the TV was working there was a 'static' across the image - like the one when there is a loose cable connection. Upon checking the PCB there was one blown resistor (RK46), when in fact previously there wasn't any evidence of a burnt out resistor or even when I checked with a multimeter.
IMHO there seems to be a hairline crack in the PCB, which caused this failure.
1. Could the problem be a hairline crack?
2. Did this cause any major damage?
3. Will changing the complete PCB (available from Hitachi) solve this problem?
Thank you in advance for your help.
If anyone has a service manual for 51SWX20B, would appreciate a copy emailed to me at email@example.com
2007-08-16, 02:36 AM
So, I replaced the IC's and checked the resistors and all were fine. Now, I started the tv back up and thinking that with a manual convergence i would be up and running. Unfortunately, this was not true. I went to do a convergence. Luckily, the lines were much more straight and organized. However, I could not move the blue lines at all, and green would not mover side to side. What could be the cause of this? I mean everything else was done according to instructions. What do you guys think?
In addition to that, I found a green jumper cable underneath the board that connects the IC to another part of the board, what is the purpose of that.
Thanks for the help so far, and in the future.
I assume you're trying to do a DCAM convergence and not the manual user convergence?
Try unplugging the TV to see if it'll reset, or run the magic focus first.
You may also need to press the "little blue button" to reset the TV/convergence - this should take you directly into DCAM. The little blue button is located near the left side of the chassis when you're looking at the front of the TV via the front access panel removed. Do not hold the little blue button in, just press it relatively quickly.
2007-08-16, 09:24 AM
What is the difference between a manual convergence and a dcam convergence?
I have left it unplugged over night. In regards to the little blue button, i have held it down while turning the tv on as per wrong instructions on a different website. and it reset the convergence completely. Also, I do not have magic focus because I kept on retrieving the overflow problem. What should I do now?
Do you think that I should replace the resistors? I checked the values via multi-meter and the resistor color band, and they were the same as listed in the post and on the b and d kit. Or Anything hardware related?
2007-08-16, 10:42 AM
As per post #230: I figure that it is a problem with IK05's IC. Could it be a problem with the resistors on the board, or a wire problem?
What is the difference between a manual convergence and a dcam convergence?
Do you think that I should replace the resistors?
Manual (user menu) convergence is available in some of the newer TVs. I just realized that your older model doesn't have this, so you must be doing DCAM.
Any number of things could be wrong - resistors, cracked solder, the ICs may have blown again - some are "knockoffs" (not OEM Sanyo) and therefore don't last, etc.
The fact that the convergence grid comes up OK though would lead me to believe there is something other than the ICs amiss, since you'd get the curved lines/3D colour effect if the ICs were shot...
Sorry I can't help you more.
2007-08-16, 11:37 AM
Thanks for all your help. I did buy the Sanyo IC's. What do you think the most possible thing is? Resistors, cracked solder, or could there be any other possibilities. But am I right that it is IK05 that does not work because I cannot move Blue at all, and cannot move green side to side? Is there any other way to manually do the convergence?
What is the green jumper wire coming from the back of the board from the IC?
Sorry, I don't have the knowledge to answer these questions. I hope that someone else here does. If you haven't replaced the resistors, then that'd be my next step, but do it quickly before you blow the ICs. There is no other way to do the convergence on your TV that I know of.
2007-08-16, 12:10 PM
How do I get magic focus back?
By pressing the magic focus button on the front of the TV. ;)
Seriously, if that doesn't work, what happens - do you get the static mode (the 9 +)? If so, press the little blue button to get DCAM and you should have magic focus back after that.
If magic focus doesn't operate, gives an error code, or goes to static mode, then there may be something wrong with the convergence still.
To be honest, I NEVER use magic focus. I do a DCAM convergence every six months to a year instead.
2007-08-16, 12:35 PM
If I go through DCAM, do i have to have everything converged before I try to have magic focus back, because I still recieve the over flow screen after the green. I figured that was because i didnt get the convergence right.
That could well be. Start DCAM in medium instead of fine. The first time you do convergence it may take you an hour. Now I can do it in about 10 minutes.
2007-08-16, 01:21 PM
Is green supposed to move side to side? and it seems as though blue is moving, meaning the color flicker to show that it is moving but the overall position seems to to stay? Is it just that i need to keep at the blue for ten to twenty minutes to move just one line?
If you follow the instructions in the DCAM thread, you can switch to move all three colours. The green should be done first using an overlay (or strings) to ensure that the lines are straight. Then you converge the blue and red to the green. If the colours don't move properly (and quickly - at the same speed), then something may be amiss.
2007-08-16, 03:55 PM
Does anyone know what could be wrong in regards to what is explained above?
2007-08-16, 04:29 PM
57, is there a way to check if the IC's have blown again?
If they have blown, I believe you would have bent coloured lines (that 3D effect) when viewing a normal channel. See the image at the bottom of post 1 of this thread. IF the picture looks normal, then the ICs are probably OK.
2007-08-16, 04:53 PM
I have curved lines but they are organized. This probably happened because of the reset of me hold down the "little blue button" while turning the tv on. Would you agree? Would you like me to post a picture later tonight?
Feel free to post a picture (you'll need to upload to a server or to a photo sharing site like Flickr and paste the URL in the post, you cannot upload to this site). I cannot comment on holding the little blue button as that does a reset of some kind if I recall.
2007-08-16, 10:39 PM
Hi guys.. Great info here.
I read everything I could find about the convergence problem and went ahead and ordered a kit. Got the new amps and resistors in this afternoon and attacked the problem with a soldering iron. That seemed to go well.
I popped the convergence board back into the TV and reconnected all of my labeled wires and turned on the tv to start a convergence. I had it going pretty well but something seemed off still. A bit of curve to the green. So I popped the board back out. Checked the solder joints. Tested the resistors. popped it back in and I can no loger hit the "little blue button" to get into DCAM mode. Nor does the magic focus way in work.