Hi guys! You gentlemen helped me with a monitor a while ago, I was hoping that you might be willing to lend your wisdom one more time. 
I picked up a non-working VisionQuest LVQ40HLA recently. When plugged in the red light comes on as normal. When I press the power button nothing happens. Press again, nothing. A third time, the light turns green and the backlights come on and stay on for five or ten minutes, nothing on screen. As long as it hasn't been unplugged it'll turn on and off with one press afterwards. Then things get weird...
I opened it up which was a battle, the dang thing had two rubber strips glued between the panel and the back plastic! Glue! I know it's a cheap TV but c'mon! Anyway, I found several bad caps on the power supply and replaced them. No change, still a black, backlit screen after the third press. So I took off the mainboard to check the larger caps, they looked like they *might* be bad. I checked them on the board with my Atlas ESR meter and they checked out fine so I didn't bother to replace them. I put it back together to check some voltages and what do you know, it came to life. Blue screen, OSD, etc.. It's alive!
I hooked up my old SNES as a video and audio source and sure enough, it was alive. However, the colours were a little off... It's hard to describe, but it seemed like some random blue mixed in here and there where it shouldn't be, maybe the reds were a bit off, etc... I wish I had taken a picture. So I figured I'd remove the mainboard again and look for cracked solder joints, probably on the connectors. I checked and found none. Upon reassembly again, the screen would turn on but only the blue edge would come on right away, maybe an inch all around. The middle would come on a few seconds later and the colours were still off. I didn't notice if it came alive right away or after the third press.
I then decided to reseat all of the mainboard connectors again, there must be something loose. This time I'm back to square one. Backlight only after three attempts, no picture. I *think* there's audio but I can't be positive, I heard a little static when I was on cable but now I'm not sure which input it's on. I've reseated everything half a dozen times with no improvement.
I did take voltage readings from the power supply somewhere along the line and I think they were all in spec, I can get some actual numbers if it helps. I should also point out that it's very chilly in my workshop so I doubt it's something overheating immediately.
What a pain in the butt set to work on... For a while I didn't think it even HAD a t-con board until I really tore it down.
So, any suggestions would be fantastic. My apologies if the pics aren't good enough, I can try for better lighting if it's an issue. Thanks!
I picked up a non-working VisionQuest LVQ40HLA recently. When plugged in the red light comes on as normal. When I press the power button nothing happens. Press again, nothing. A third time, the light turns green and the backlights come on and stay on for five or ten minutes, nothing on screen. As long as it hasn't been unplugged it'll turn on and off with one press afterwards. Then things get weird...
I opened it up which was a battle, the dang thing had two rubber strips glued between the panel and the back plastic! Glue! I know it's a cheap TV but c'mon! Anyway, I found several bad caps on the power supply and replaced them. No change, still a black, backlit screen after the third press. So I took off the mainboard to check the larger caps, they looked like they *might* be bad. I checked them on the board with my Atlas ESR meter and they checked out fine so I didn't bother to replace them. I put it back together to check some voltages and what do you know, it came to life. Blue screen, OSD, etc.. It's alive!
I hooked up my old SNES as a video and audio source and sure enough, it was alive. However, the colours were a little off... It's hard to describe, but it seemed like some random blue mixed in here and there where it shouldn't be, maybe the reds were a bit off, etc... I wish I had taken a picture. So I figured I'd remove the mainboard again and look for cracked solder joints, probably on the connectors. I checked and found none. Upon reassembly again, the screen would turn on but only the blue edge would come on right away, maybe an inch all around. The middle would come on a few seconds later and the colours were still off. I didn't notice if it came alive right away or after the third press.
I then decided to reseat all of the mainboard connectors again, there must be something loose. This time I'm back to square one. Backlight only after three attempts, no picture. I *think* there's audio but I can't be positive, I heard a little static when I was on cable but now I'm not sure which input it's on. I've reseated everything half a dozen times with no improvement.
I did take voltage readings from the power supply somewhere along the line and I think they were all in spec, I can get some actual numbers if it helps. I should also point out that it's very chilly in my workshop so I doubt it's something overheating immediately.
What a pain in the butt set to work on... For a while I didn't think it even HAD a t-con board until I really tore it down.
So, any suggestions would be fantastic.
My apologies if the pics aren't good enough, I can try for better lighting if it's an issue. Thanks!
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