CurtPalme.com Home Theater Forum

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

here is a youtube video explaining how its done but with a special tooling device.

https://www.youtube.com/watch?v=FG2HO8K38bs

Athanasios

stefuel · Posted: Sun Dec 09, 2012 12:40 pm Post subject:

Well this morning it fired right up normally. The only thing I did last night was press hard on the ribbon connection to the interface board. Mac listed two types of conductive film for this application. One required heat and pressure for activation and the other just pressure. I'm going to try the pressure one first. If that doesn't work then I'll try pressure and heat.
From what I read about this film, it can look to be attached and mechanicaly can be but if it lifts away even a little it can loose conductivity.

Both of them require heat to be removed and repaired or replaced and as I said these ribbon cables do get quite warm to the touch. In this case the ribbon comes straight up out of the top edge of the panel. Then it bends 90 degrees to where it attaches to the interface board. The whole ribbon is only about a inch long and when you put the interface board 90 degrees to the LCD panel, the ribbon is spring loaded wanting to pull away from the board. That plus the heat could be the cause of the problem. If you read those sheets that Mac posted, one of them actually states that clamps should be used in flex applications.

stefuel · Posted: Sun Dec 09, 2012 2:01 pm Post subject:

Upon further reading, the film or adhesive it's self is not conductive. It's the particals contained in it that is and why there is no conductivity from connections to the side. For conductivity to exist, the particals must touch both parts. If the film softens and pulls away even ever so slightly, conductivity is lost. In looking at the tooling, the pressures and temperatures are nothing special. Probably the hardest part of the attachment proceedure is alignment of the two parts.
For this a camera scope is pointed at the connection point and a 3 axis tooling mount is used to perfectly line the parts up.
With this in mind, I'm not going to remove it and re-attach it. I will simply try to re-press it as it is already aligned.

stefuel · Posted: Sun Dec 09, 2012 11:08 pm Post subject:

Ooooops
I might have just cut my project short....Short, yep that's the right word for it.
I was using my drafting pencil, you know the kind that you click like a pen and it pushes out more lead. it has a fine point and I was using it to press on each connection pad on the ribbon cable at the interface board. The lead snapped and the metal tip of the pencil came down on some of the exposed connection area. The picture went blank. Hopefully I popped a smt fuse but won't have a chance to shag it until tomorrow night. I know STUPID. Should have used something plastic.

Dumbass

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

Easy come, easy go Wink

**AnalogRocks** · Posted: Mon Dec 10, 2012 7:39 am Post subject:

stefuel · Posted: Mon Dec 10, 2012 11:04 pm Post subject:

Sorry. N0 gut-wrenching explosions. No blood and guts. Just there was a picture and then, NOT. There was sound and back light just no picture. That's OK though. I learnd a important lesson. First, cut down on the coffee. Second no metal probes on live circuits and third, don't F-up when you have to answer to this bunch Laughing

Anyway, I found the problem. I popped F1422 on the back side of the input board. It's a smt fuse about the size of a flake of pepper. Of course I don't have it but I do have a little piece if wire to jump it out and see if all will be well.

**AnalogRocks** · Posted: Tue Dec 11, 2012 12:31 am Post subject:

stefuel · Posted: Tue Dec 11, 2012 12:32 am Post subject:

It's Alive...
AND since I did a half-assed re-press of the ribbon connection at the interface end, it fires up perfectly cold.

stefuel · Posted: Tue Dec 11, 2012 12:37 pm Post subject:

My conclusion (at least in this case) is it's not the panel it's self or the ribbon cable connections at the panel. It's the ribbon it's self (perhaps) or most likely the ribbon connection at the interface. After rubbing down hard on that connection two days ago, it has done two perfect cold starts. Now I'm going to make my self a cheap tool using needle nose vice grips to re-press all 8 connection points. I think that will do it as it only requires a minimum of 15 lbs pressure to do it. Thumbs Up

stefuel · Posted: Sat Dec 15, 2012 3:51 pm Post subject:

OK, here's what I have done. I took the LCD panel right off the TV's frame and placed it on a clean flat surface. I took two pieces of machined flat aluminum and sandwiched the PCB/ribbon connector between them and used a real stiff hand clamp to squeeze them together. I attaced a probe from a digital thermometer to the aluminum. Then I used a heat gun to raise the temperature of the aluminum block to 200 degrees. When it droppes back to room temp, I'll re-hang the panel and see what happens. I have to get this tv back together before I forget where the 200 screws go that I took out Laughing

I have pictures but am waiting for the batteries to re-charge so I can download them to the pc.

larryk · Joined: 23 Aug 2007 Posts: 106 Location: Edmonton Alberta

I'm not sure what access to the connections there is but there is a treatment that may help out the problem and possibly ensure it doesn't come back. I have used this product on many occasions where it has saved the day and brought dead things back to life. I introduced this material to our local Filmmaking coop where it is used extensively. They call it magic sauce. It's called Stabilant 22.
What you would do is used Stabilant 22A which is cut with isopropyl Alcohol. That makes it thin enough to wick into the edge of the connection and when the alcohol evaporates, leaves a contact enhancing liquid that lasts up to 15years. I have saved CRT projectors, video cameras, automotive sensors, etc. etc. Everything I build or repair gets treated including computers. If you can track some down you may want to try it.

Larry

stefuel · Posted: Sat Dec 15, 2012 6:17 pm Post subject:

Well that's a hoot. I do think I solved the problem with the cable I've been looking at, only to disturb something in one of the other seven. Fixed one problem and create another (total different symptom) Laughing

stefuel · Posted: Tue Dec 18, 2012 11:24 am Post subject:

I now know what the problem is. The ribbon connection on the far right is out of position and pressing it harder only made it worse. With the strongest magnification I have here at this time I can see that the ribbon is off enough to connect with two pads at the same time. I have ordered the correct ACF tape and a digital microscope to aid in re-alignment. The tape will be here this week but the microscope won't be here until next week. When that arrives I will post a picture of the problem before I attempt to repair it.

Now I'm having fun.

stefuel · Posted: Sun Dec 23, 2012 2:57 pm Post subject:

Conclusion
At least in this case the problem is the ribbon it’s self or the chip attached to it, mounted midway between the LCD panel and circuit board.
The first thing I noticed was, every time I removed the LCD panel from the chassis, the problem changed or got worse.
Touching the ribbon between the chip and LCD panel caused no reaction.
Touching the ribbon between the chip and circuit board did cause a reaction.
Rubbing down the connection at the circuit board seemed to improve things.
Re-doing the connection at the circuit board did not solve it. (and that was very time consuming)
Putting a clamp on the chip only seemed to make things worse.
I am going to make one more attempt to inspect the ribbon, mostly out of curiosity because I don’t think I can fix that. The traces are not exposed and are probably to small for a pen to work.