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.