Picture alignment off


Moderator: Angel

Forum rules
appleads
TV Repair Jedi
TV Repair Jedi
Posts: 85
Joined: Fri Apr 17, 2015 7:07 pm

Picture alignment off

Postby appleads » Mon Nov 09, 2015 11:51 pm

I recently saved a HL72A650 from the scrap yard, and after replacing the ballast, and installing two new capacitors on the power supply, it's working great. Except for one thing. The picture is 4 inches too high. I went into the user menu first and tried to adjust position, but it only moves a little bit. Then I went into the service menu and adjusted the picture to be perfectly centered vertically and horizontally. But the image is still cutting off the top of the picture and showing a 4 inch black band at the bottom. The mirror inside looks okay, doesn't appear to have shifted. The light engine is properly fit into the chassis. I dug down and checked the DMD chip and it was slightly loose, so I pushed it all the way in, thinking this was the issue, but it wasn't. I even fiddled with the "Never fiddle with those three screws" beneath the white caps, but it didn't seem to have any effect on the picture. Now I am beginning to suspect perhaps the light tunnel is to blame. I've fixed two sets with mirrors that have come loose in the light tunnel (creates an annoying vertical shadow down the side of the screen) but that's not the issue here. I doubt the light tunnel mirror is at fault. Now I am aware that the "scope" part of the tunnel has adjustment screws, so I guess that's where I'll start next, but if anyone has any ideas of what else it might be, please let me know. Thanks for any help you can give me. Help the environment. Save a Samsung.

appleads
TV Repair Jedi
TV Repair Jedi
Posts: 85
Joined: Fri Apr 17, 2015 7:07 pm

Re: Picture alignment off

Postby appleads » Sun Nov 15, 2015 1:16 am

I am baffled. The three "don't fiddle with" screws don't seem to have any effect upon the picture position. I've loosened and tightened them all and can't see that they are making any difference whatsoever to anything. I'm sure this isn't right, but I refuse to surrender and call in a Samsung tech. I've tried the tiny screw on the top of the "telescope" portion of the light tunnel. It also didn't seem to change anything. There's always the second tiny screw that's "horizontal" on the telescope but I doubt this would affect vertical position. I have three people who have expressed an interest in buying this set, but with it out of calibration, I doubt I can sell it. Would be nice to know what exactly is wrong and what it needs to fix it. If anyone has any thoughts, I'd sure appreciate hearing them.

appleads
TV Repair Jedi
TV Repair Jedi
Posts: 85
Joined: Fri Apr 17, 2015 7:07 pm

Re: Picture alignment off

Postby appleads » Sun Nov 15, 2015 1:38 am

Well I've found an excellent post on Justanswer and will try the advice offered to someone with exactly the same problem. Will update this soon.

appleads
TV Repair Jedi
TV Repair Jedi
Posts: 85
Joined: Fri Apr 17, 2015 7:07 pm

Re: Picture alignment off

Postby appleads » Sun Dec 06, 2015 4:01 am

Finally, success. It turns out that despite loosening the three "don't fiddle with" screws, my alignment didn't change. Because of age, the board/dmd chip alignment was sort of stuck into position. With the three screws loose, I pried the board a little and suddenly it was loose and could be adjusted. I agree, it's a lot easier if you have a mirror or an assistant set up to help you, but I had neither. So with some trial and error and about 10 trips from back to front make an adjustment, check it again, make an adjustment check it again, I was finally able to line everything up. I must say the results were VERY satisfying. My picture is now in perfect alignment and my sense of accomplishment is through the roof. DO NOT BE INTIMIDATED. This is a surprising logical and simple process. The board has about 1/2 inch of vertical play and about 3/8 ths or 1/2 inch of horizontal play once it's "free" and the three screws are loose. I got it close to where I wanted, put a little bit of torque on the screws so it wouldn't shift around too easily and then tapped it delicately into position. A tiny bit of movement goes a LONG way. Invoke the service menu and go through the test patterns to confirm you've got it right. You can fine tune it in the service function a little to get it exact. It's easier than you might think.


Return to “Samsung Discussion”