Home Theater Forum and Systems banner

1 - 12 of 12 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
Hitachi 43fdx01b

Hello all first post for help and troubleshooting here hopefully.

I just recently acquired this tv for free and I am hoping to fix it. Here is the story of the tv history that may help in trouble shooting.

The woman who originally had the tv noticed a slight convergence issue with the red vertical it bowed out only very slightly in the middle of the cross hairs. It was annoying enough to her (and she had been looking for an excuse to buy a new tv) that she gave it to a friend of mine. He gave it to a friend of his on the condition that he fix it and not just dismantle it.

Unfortunately this person decided to see if the blue color gun would fit in his own tv so he removed the part without checking first if it would fit his application. Needless to say it did not. So he put the gun back in the original unit and gave the set to someone else. That person is not much of a fix it yourself kind of guy and his wife told him to rid the living room of the aforementioned non working tv. Thats where I come in :yay2:

I get this tv for free and start troubleshooting it. My first thought is that the STK convergence chips are mildly toast, because of the small red distortion from the original owner. So no problem there. However now a new problem exists, I assume that the individual who removed the color gun installed it improperly or fried something else in his little dismantling party. The blue convergence line is WAY off to the right side of the screen, and very distorted at the bottom looking like a little lightning bolt zigging itself at about the bottom two inches or so.

I spend about two hours or so fiddling around with convergence settings (which are very limited in the on screen menu. Not much happens and there is no way to get the blue even remotely close to lining up left and right on the cross hairs.

I notice after I disassemble the tv that the yoke collar (I think thats what its called) rings have been moved significantly from factory as there are white marks that are on all three (RBG) yokes and only this one does not line up anymore. I think to myself "great this should fix it!" so I try and line up the white marks back to the original position. I do this and the blue line is still way off to the right. So obviously there must be something else going on...

I take off the back of the tv to see the topside of the color guns and their focusing collars. Something about them makes me pause and think. Something is definitely awry here. This being only the second RPTV I have disassembled it takes me slightly longer than it would take most of you folks to figure out exactly what is wrong in this picture. But finally I notice that the focusing lens of the blue gun is on BACKWARDS!! so I pull it and flip it around, vwalla! presto! and various other exclamations at my wizardry and general self importance :dumbcrazy: fly through my mind. I check the convergence and yup sure enough now the blue line is very nearly where it should be.

Unfortunately i still have a convergence issue of some magnitude. thought now I can get the lines on the convergence screen to line up the edges are very distorted on all colors. Mostly the vertical but some to the right side horizontal as well. Now I realize the STK chips are most likely bad however I wish to verify that no setting on those little yoke collars or anything else would cause this same issue. I can not seem to get the tv back to its original state of only a slight distortion in red. The troubleshooting continues!

Any advice or ideas (crazy or otherwise) would be very much appreciated in light of my limited RPTV experience. Thanks in advance for your help.

Semper Fi

P.S. I shall upload some images when I can downsize them
 

·
Plain ole user
Joined
·
11,121 Posts
Can you adjust the problem at the edges? If the correction works then the ICs are likely good. You may need to do a convergence reset and start from scratch, but before you do you need to do some serious study of the entire convergence and geometry setup.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #6
Unfortunately I have not found an adjustment that will alter the warping of the lines at the bottom or the right side. When I move the tabs on that yoke it just moves the entire blue cross line in various circles of different sizes (depending on which tab is moved) and also slightly focuses it. But the red and green are also warped at the bottom. The only setting that I can manually adjust with a knob is the vertical size of all three colors found those knobs on the front of the convergence board when I pulled it out to look for cracked solder joints. Is there a more in depth convergence menu I can use for this tv? The only one I have found thus far is by pressing the button on the front of the tv or in the menu, all it allows you to do is move red or blue up down and left right. Now bow, tilt or any other setting. Thanks for the quick response. :)
 

·
Registered
Joined
·
14 Posts
Discussion Starter #7
Hey! after searching around a bit I found the little hidden blue button for convergence! I am going to try setting that up in basic mode and see how it does. I shall let ya know what pops up. And how well it does or does not work.

Thanks!
 

·
Plain ole user
Joined
·
11,121 Posts
Get the service manual, read the first ten posts of the convergence thread, and make sure that you understand what you are doing before making any more adjustments. If you cannot adjust the point convergence in a significant part of the screen you probably have a bad IC. If you can adjust the H & V for red, green, blue over all of the screen your output ICs are working.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #9
I have read your convergence post several dozen times :) very helpful I might add. I was just having some issues attempting to find how to access the controls on this tv. However I believe you are correct with the ics being ok as I can move every color in every direction across the board. With the blue being as far off as it is though Im almost positive it had something to do with the gun removal and reinstalation by one of the previous owners. I will get back to you as soon as I fiddle with it some more.
 

·
Plain ole user
Joined
·
11,121 Posts
You are likely correct. You need to study the service prodecures carefully so that you understand how to align it. Each brand and model can be very different, which is why I suggest to always have the service literature before doing anything.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #11
I downloaded the service manual and have been studying it very closely. I shall check through it carefully before I get to gung ho on aligning things. One thing I noticed while in the blue button convergence screen was that I can move the blue up and down at any point across the screen but not left or right, the other colors can move just fine all around, which leads me to think possibly a bad resistor or ic, but I shall check more into the manual before I make a final call on that. I shall post a picture of the test grid sometime tomorrow for you to have a look at and see what you think. Thanks again and I do hope I am not boring you too much :)
 

·
Plain ole user
Joined
·
11,121 Posts
If you cannot move one color vertically or horizontally, change both ICs and test all resistors. Be sure to use the proper Hitachi kit for your model.
 
1 - 12 of 12 Posts
Top