CurtPalme.com Home Theater Forum

stefuel · Posted: Fri Dec 07, 2012 12:32 am Post subject: Well, that's no fun!!!

I picked up a free Sony Bravia 46" flatscreen (KDL 46V4100) that was supposed to have a problem with the picture around the edge. It's been bouncing around the back of my service truck all day. I brought it in the shop and plugged it in. What problem??? It's been running fine for over two hours. Perhaps it was the two huge potholes I hit that fixed it Laughing

I was kinda looking forward to taking it apart but not yet I guess.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Don't worry. It will come back...... Twisted Evil

stefuel · Posted: Fri Dec 07, 2012 1:16 am Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Most likely a bad panel..... Sad

**Curt Palme** · Posted: Fri Dec 07, 2012 2:30 am Post subject:

I can answer this one! Smile

Yes, Sony panels are known for delamination between the layers. I had that same set here (the second one so far). and it was all dark and weird colors. I wouldn't believe that the panel was bad as Mac told me over the summer, so I opened it. I went out for dinner and forgot to unplug the set, so it was face down for a couple of hours on my padded bench. Came back, saw the glow on the bench, flipped up the set, and lo and behold, everything worked great.

'what does Mac know, I'll show him' was my immediate thought.

Turned off the set, left it an hour, it was fine. Left it off overnight, and it was back to being dark and faded. LEft it on upright for an hour, and it snapped into place.

I've got a local Asian buddy that claims he pulls the panels apart and manages to fix the odd one by clamping something together around the edges, but that's all he's told me so far. I usually sell him my reject sets for $25 each..

**AnalogRocks** · Posted: Fri Dec 07, 2012 8:10 am Post subject:

nettwerkjohn · Posted: Fri Dec 07, 2012 12:06 pm Post subject:

and hamsters?

stefuel · Posted: Fri Dec 07, 2012 12:32 pm Post subject:

It's back. Probably didn't see the problem last night because it was on while I was looking for a HDMI cable to hook it up.
Obviously heat related. Turned it on this AM and the right side was rolling like out of sync. In five minutes the rolling stopped and left a little discoloration just below the top right corner. A gental tap on the top right corner and that cleared up. I have a task. Laughing

**Curt Palme** · Posted: Fri Dec 07, 2012 2:23 pm Post subject:

Yup, same problem. It was that sync problem that had me completely convinced that it wasn't the panel. But.. it is.

**AnalogRocks** · Posted: Sat Dec 08, 2012 5:27 am Post subject:

stefuel · Posted: Sat Dec 08, 2012 11:14 am Post subject:

OK, I'm having a little bit of fun (not with little furry animals) but that may be cut short with a quick fix.
It seems the panel it's self is not the problem. It seems as though the ribbon cable that actually passes data to the panel is somehow glued in place on the panel side and that is where the delamination is happeneing. I'm not sure how it passes data being glued in place but it does. My theory is that it just has to be in real close to pass the data and when it starts to pull away it can't.

I now understand the comment Curt made about his friend "clamping" the panel for a fix. I wish I knew what the adhesive is that they used for the connection. Off to the laboratory. Igor, throw switch number one. Laughing

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

ther are a handful number of conducting glues used in the industry, they're not cheap. Since I write from Europe I can't help with available glue types over there, but look after them.

stefuel · Posted: Sat Dec 08, 2012 1:37 pm Post subject:

Well after removing a bazillion screws to get the back, outer front and inner metal LCD frame off, I think I found the problem. There is two interface boards (right side and left side). They are part of the LCD panel assembly, hard wired to the LCD panel. Each one has 4 ribbon cables. On the panel end they are laminated directly into the plastic. On the interface end they are soldered, pressed glued or whatever to the board.
In my case I know that it is the right side far right ribbon cable that is causing the problem. Just touching that cable causes a reaction. The rest do not. I do not think the problem is where the cable enters the panel. Touching the cable or pressing the panel where it enters causes no reaction. Touching the cable at the interface shows minimal reaction BUT touching the cable where it bends over the top causes the most reaction.

There is more then data passing through these ribbon cables as they get smokin hot (well perhaps not "smokin" but real warm to the touch). Now that it's been running for a while it is stable and very hard to cause any reaction touching anything. Time to break out the refrigerant bottle. Wink

stefuel · Posted: Sat Dec 08, 2012 2:45 pm Post subject:

Here's the bugger

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

That adhesive as you call it is special stuff where the current only passes directly through it and not off to any side. It requires heat and special tools to apply and the procedure is not cut and dry. Plus the stuff is very difficult to find. Can't remember the name of it off hand but it's probably in my PC somewhere.

I was unable to repair a device Curt sent me where the ribbon was delaminated. I researched the materials and the procedure and then couldn't find anything in smaller quantities. I was going to try to gamble without the special tools but in the end had to bail on it.

Even if it's not delaminated they can sometimes break the trace in the ribbon. If that's the case and the trace is accessible, meaning it does not have a coating over it, you can get a trace repair pen and just draw a new trace. Those are easily available.

stefuel · Posted: Sat Dec 08, 2012 4:45 pm Post subject:

"Even if it's not delaminated they can sometimes break the trace in the ribbon. If that's the case and the trace is accessible, meaning it does not have a coating over it, you can get a trace repair pen and just draw a new trace. Those are easily available. "

This is what I think the problem is. I will have to swing the right side board over and see if the traces on the under side are exposed. They are not on the top. Going to try the refrigerant thing first to see if I can exactly isolate the problem.

stefuel · Posted: Sun Dec 09, 2012 12:38 am Post subject:

This is weird. I could not re-create the condition by cooling it down. I even froze the top corner of the panel, the ribbon cable and interface board.
Tomorrow morning I will fire it back up just long enough to see if it is bad. Then I will take a heat gun to just the panel and not the ribbon cable to see if pre-heating the panel makes it go away.

Ron,
The ribbon cable does not show any signs of solder where it is attached to the board. This may be where that glue is used.
In looking at this, this is the only place that Curt's friend could clamp to make a connection. I tried squeezing the panel it's self where the cable enters and nothing happened.
If I knew the working temperature of that glue/adhesive, I could sandwich it between two pieces of bar stock, attach a digital t-stat to the bar stock and heat it to the desired temp then let it cool naturally, then remove the bar stock and see if it re-stuck.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Let me see if I can find that info I had. 395 degrees F seems to come to mind but let me check.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Here's one link that explains what it does. I'll keep looking for the procedure one.

http://www.acffilm.com/

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Here's a 3M paper somewhat explaining the procedure. I see a lower temp then I stated earlier but could be just a different brand.

http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtnxfVMxz6EVuQEcuZgVs6EVs6E666666--

And another paper: http://multimedia.3m.com/mws/mediawebserver?mwsId=hhhhhjK59tWIam3JDN3mEN3QVLK2VtK58LihVLihVhhhhhh--