Sanyo DP46848

[hoadle]

Hi,
I have a Sanyo DP46848 here that shows a really messed up picture.
When I turn on the screen had vertical line & they moving (look like the "No Signal" message) at first attach
about 15 to 20 min the screen show 1/2 screen look final another is dark see second attach
about 45 to 1 hour the screen is normal see attach third
is there a common T-con failure that does this or is it simply the main input board failure?

[tom66]

Re: Sanyo DP46848

This could be a bad LCD panel or a bad T-con. It is unlikely to be the main board. It could also be a low +5V or +12V to the T-con board. Do you have a digital multimeter?

[hoadle]

Re: Sanyo DP46848

Thanks for the replies, I had a digital multimeter "Fluke 189"
I check the mainboard to T-con about 12V to 19V. I think maybe the Tab Bonds or bad panel

[hamdin]

Re: Sanyo DP46848

I had a similar problem. I checked all the boards, they all seemed fine. The caps in this tv seem like a good brand (rubycon). In the end, I had to take out the LCD frame and play with the ribbons, which solved the problem, similar to this post:

I hate to dig up this thread again, but I (think) after over a year with this issue, I finally solved it. Hopefully.

This morning I was feeling a little brave. Actually, more like I've been sick in bed and trying to watch the stupid thing I got frustrated and grabbed my laptop. After digging through the web for hours, I came across a video that was VERY helpful in solving this case. This video here: http://www.youtube.com/watch?v=purk_SyiT44

This isn't the same TV, and it isn't even the exact same problem, but it's close. It led me in the right direction. Since I can't stand being sick, and I hate even more to be laying in bed trying to watch that PITA television, I grabbed a screwdriver and got busy.

This is probably the 5th time I've tore this thing apart. But this time I didn't have to go as far. The only thing that needs to be removed is the front bezzle by removing the screws around the outside on the back. The front bezzle comes right off, so be careful, especially since the speakers will still be connected, so just carefully lay the bezzle down in front of the TV. This will reveal the metal frame around the LCD. This also needs to come up. There's a number of screws around the outside on the very front of the frame. Take those off, and that frame will slide right off.

After the LCD frame is off, you will notice the 12 ribbon cables along the top of the screen. You can see them clearly in the video I posted. I went ahead and plugged the TV in and fired it up. When it was on, I lightly pressed on the front of those ribbon cables to see which one was causing trouble. For me, it was the 2nd one from the left. I had a few pieces of one-sided sticky foam laying around, so I cut it up into 12 pieces and stuck it on the front of each of those ribbon cables. I put a piece of electrical tape over the top for good measure. While the TV was on I grabbed the metal LCD frame and put it on. As soon as I got the first screw in on the left side, boom, the problem came back even worse. The left half of the screen stayed solid dark, unlike before where it was just flickering. So I drew a conclusion that putting MORE pressure on those ribbons made it worse. I took the frame off again, and removed the tape and foam from the ribbon that was causing problems. I even removed the rubber piece to the corresponding ribbon on the top inside of the metal frame. I tossed the frame back on and the picture was like brand new. It's been on all day without a single problem. I'm sure this is only temporary, but I'm glad to be able to enjoy my TV at least a little while longer.

If you're having this same problem, the first thing I would do is remove the rubber on the inside of the frame for the cable that is causing you problems. If not, you could always go the other way and add pressure by using some foam or rubber or whatever you have laying around. The best thing would be to check out that video, everything was explained very clearly and it was very helpful.

Good luck, and Happy New Year!

Cheers.

One thing you have to be careful about is that after you take off all the screws for the frame, there is still a metal component at the top of the lcd panel that is sticking out of the circuit board which sits within a hole in the metal frame. You have to push it in with a screwdriver while removing the metal frame. I didnt know about it and I bent it while trying to take the frame out. When that part touches the frame, it messes the picture (looks all white). Fortunately i was able to bend it back so it wouldnt touch the frame. After playing around with the ribbons, i reassembled it while the tv was on. I had to carefully put the screws back in (some screws mess the picture when you tighten them too much), while not messing the picture. The TV is still a bit touchy but it works if you leave it alone.