LCD Monitor has rough screen with ripples

[Rasz]

test with same signal connected to have comparison

[rockblues]

test with same signal connected to have comparison

Same signal connected? Do you mean attaching screen to HDMI then to VGA?

Test Setup: Not plugging Monitor into PC. Simply plugging in power. Seeing Sell self test screen. White text box on black background.
Monitor is lying flat on a table. Front facing down. Back cover off. Lifting up panel off table to see screen action.

Soldering The Strips: The guy with the Fluke heated the back of the board so as to not injure the tape. The board here is connected to the panel. Can't remove it.
If I heat the tape with the soldering iron, I'll melt the strips. Liquid Flux is on it's way. Also the SMD Removal Alloy.

Deoxit cleaning got rid of many lines.  Ready to test. Thanks!

[rockblues]

Plugged in monitor panel. Solid white screen with horizontal bar. Changed to Mouser 470uF 35V caps and the one at 330uF 35V firmerly 220uF 25V

Now see blue - green - white - black screens - all have horizontal lines. Slideshow of colored screens. Can't turn the monitor on / off.

Closed the case and hooked up monitor to PC via HDMI and VGA - same as above.

No Dell Self test anymore = white box on black screen when monitor is only powered not connected to PC

[rockblues]

Sprayed Deoxit on ribbon connector on the main board and on the panel + again on ribbon connector ends. Colors gone. Black + white text box came back + power only.
Switched back in the power board I bought with Dell caps. Then switched back to power board with mouser caps (470uF 35V Panasonic Low ESR High Ripple Current) + ribbon that came with replacement boards.

Both times I get black screen + a white box = Dell Self Test. No more colors on the screen when doing Dell Self Test.
Text is garbled and not clear. If anything the Board with the Mouser Panasonic Low ESR High Ripple caps is sharper.

Now, text box is in the center now, not the left side.

[rockblues]

Opened up the panel. with the monitor on, pressed on each of the 8 strips. The white text box moved to the left side. Then when powered on again, it was at center position.

Something's wrong with the LCD. Or the strips connecting the LCD to the board.

[Rasz]

Same signal connected? Do you mean attaching screen to HDMI then to VGA?

same as first  picture with windows desktop, so you at least see if anything changed for the better

I'll melt the strips.

kepton shouldnt melt, besides you should try just heating them up first, not soldering
heating up will soften the glue and could cure it if the fault is there
soldering flex to pcb is extremely difficult, I wouldnt even try without practicing on scraps of another tv

Changed to Mouser 470uF 35V caps and the one at 330uF 35V firmerly 220uF 25V

there was never anything wrong with caps in this monitor

Now see blue - green - white - black screens - all have horizontal lines. Slideshow of colored screens. Can't turn the monitor on / off.

this is panel self test

Opened up the panel. with the monitor on, pressed on each of the 8 strips. The white text box moved to the left side. Then when powered on again, it was at center position.

this box always moves around, its moving to prevent screen burnin in case someone leaves turned on monitor with no signal ....
connect computer with a colorful picture to see if anything is changing when messing with ribbons

>If anything the Board with the Mouser Panasonic Low ESR High Ripple caps is sharper.

impossible = from the sounds of it you only got the impression something was making a difference while messing with the panel, all the poking and prodding was for nothing without good baseline (same picture on the screen)

[rockblues]

Same signal connected? Do you mean attaching screen to HDMI then to VGA?

same as first  picture with windows desktop, so you at least see if anything changed for the better

Right. When I reattached the monitor HDMI then VGA , both times I got solid colors (red, blue, green, white). No windows desktop blue screen.
Then I took the monitor apart and again sprayed Deoxit on the ribbon connectors, and got the black screen back.

Since I now have the black screen with the white text box (garbled), I'll hook it up again to the PC and see if this time I get the windows blue desktop.
BTW - using a replacement power (mouser caps) & main boards - just in case there was damage to either HDMI or VGA ports (main board).

Results:
HDMI - 1st screenshot at start of thread - Dell Caps - dirty image
VGA - Lines are less. Double image Win Logo - Mouser / Panasonic Low ESR High Ripple Caps / Power Board
HDMI - Lines slightly less - Triple Win Logo - Mouser / Panasonic Low ESR High Ripple Caps / Power Board

[rockblues]

I'll melt the strips.

kepton shouldnt melt, besides you should try just heating them up first, not soldering
heating up will soften the glue and could cure it if the fault is there
soldering flex to pcb is extremely difficult, I wouldnt even try without practicing on scraps of another tv

What technique do you suggest for heating the tape strips? Thanks!

I see no change when touching each of the 8 strips. Do I heat up all strips? How do you heat up kapton?
The Fluke video - the tape was heated by heating the other side of the board. Cant remove the digital board under the flap on the back of the monitor panel.
Have to try another way.

Found this - Here- the person uses tin foil wrapped around a soldering iron that is wiped with a wet sponge to lower its temp before touching the tape.

How to Remove and Re-attach LCD Ribbon From a PCB With a Fine Pitch
https://www.instructables.com/id/How-to-remove-and-re-attach-LCD-Ribbon-from-a-PCB-/



2:20 - Kapton tape melts 500F





Kapton - Wikipedia
https://en.wikipedia.org/wiki/Kapton

DUPONT™ KAPTON®
https://www.dupont.com/content/dam/dupont/products-and-services/membranes-and-films/polyimde-films/documents/DEC-Kapton-summary-of-properties.pdf
Kapton® polyimide films retain their physical properties over a wide temperature range. They have been used in field applications where the environmental temperatures were as low as -269°C (-52°F) and as high as 400°C (752°F). Complete data are not available at these extreme conditions, and the majority of technical data presented in this section falls in the 23 to 200°C (73 to 392°F) range.

Kapton Tape
https://reprap.org/wiki/Kapton_Tape

[rockblues]

Flat tip soldering iron 250C wrapped in Aluminum foil. Went up and down each strip (2X) 90 degrees a few sec dabbing many points.

Dell Self Test - Garbled text. Both VGA and HDMI have double Win Logo image. Horizontal Lines.

Dell Self Test
VGA Connected
HDMI Connected

[jpanhalt]

Flat tip soldering iron 250F wrapped in Aluminum foil. Went up and down each strip (2X) 90 degrees a few sec dabbing many points.

Dell Self Test - Garbled text. Both VGA and HDMI have double Win Logo image. Horizontal Lines.

Dell Self Test
VGA Connected
HDMI Connected

Do you  understand the difference between °F and °C?   250°F is barely above the boiling point of water.   It will not melt any solder you are likely to be dealing with.   It will melt some interesting alloys, such as Wood's metal.

From your comments here and elsewhere, I think  you are over your head with this problem.  Get a new one and stop wasting your time. 

[Rasz]

Flat tip soldering iron 250F wrapped in Aluminum foil. Went up and down each strip (2X) 90 degrees a few sec dabbing many points. Horizontal Lines.

were you doing it while monitor was on? and did the picture change at any point?
this would mean its not the strips, Tcon chip and glass left

Do you  understand the difference between °F and °C?   250°F is barely above the boiling point of water.   It will not melt any solder you are likely to be dealing with.   It will melt some interesting alloys, such as Wood's metal.

he wasnt supposed to melt solder, _there is no solder there_ , its glued
going over with soldering iron is a perfect test for bad connection under the strip

[rockblues]

Flat tip soldering iron 250F wrapped in Aluminum foil. Went up and down each strip (2X) 90 degrees a few sec dabbing many points.

Dell Self Test - Garbled text. Both VGA and HDMI have double Win Logo image. Horizontal Lines.
Dell Self Test
VGA Connected
HDMI Connected

Do you  understand the difference between °F and °C?   250°F is barely above the boiling point of water.   It will not melt any solder you are likely to be dealing with.   It will melt some interesting alloys, such as Wood's metal.
From your comments here and elsewhere, I think  you are over your head with this problem.  Get a new one and stop wasting your time.

Hi. You are right!! 250C - Thank you!!

Definitively over my head here. Studio Audio Engineer / musician. I've fixed a dead LCD that had bad caps before. This one is not an easy repair. And like you said, it might be best to just buy a new monitor.

Did you notice when I applied Deoxit, how that cleaned up the lines on the screen? Cleaning the ribbon connectors to get rid of LCD Lines? That worked for a person in Tamil. He used a pencil eraser. Did you know that? Now you do. I posted that video as well. 1st page of this thread. I have two flat ribbons from the main board to the board under the panel flap that I switched back and forth just in case one was damaged.

jpanhalt - This is a great place to L.E.A.R.N. We do this by test and measurement. Add a positive voice. Seems like you might want to expand on this problem here with your intense IQ and brilliant knowledge.

BTW - Did you know Kapton melts at 500F? The speaker did say Fahrenheit not Celsius. 2:20 in the video I posted. If you didn't know that, now you do.

(500°F − 32) × 5/9 = 260°C

[rockblues]

Flat tip soldering iron 250F wrapped in Aluminum foil. Went up and down each strip (2X) 90 degrees a few sec dabbing many points. Horizontal Lines.

were you doing it while monitor was on? and did the picture change at any point? this would mean its not the strips, Tcon chip and glass left

No. Monitor was off when I applied heat. Temp = 300C = Middle of the dial Tabiger variable soldering iron: 60W Temp Range: 200-450C

[rockblues]

Tcon chip and glass left

Hi. Rasz Thanks! How close does the TCon Chip have to be to number wise to what I have installed here? TCon Chip - HiMax HX8861-K 73DFCG 610NTAGC KRQQA 60497
You mentioned a replacement Chip: https://www.aliexpress.com/item/32850239152.html

Have some practice boards on the way from China where I can add / remove chips using SMD alloy and Liquid Flux.
I might just order the chip you suggested and see what happens. Throwing this out otherwise except the parts (boards / cables / case / stand).

[rockblues]

The chip may not be the issue.
Any of the tiny resistors and capacitors along that wide strip of circuit board can be faulty or not making a good connection to the traces on the board. On of the voltage regulators on that long board (looks like there's some on the left side in the picture but it's too low res to know for sure) could output an unstable voltage that could affect one of those ICs...

The problem may also be a poor contact between the film strips that come from the actual panel to the wide circuit board... those are almost impossible to fix by regular folks like you.
You can try to see if this is the problem by gently pressing on those strips of film / flat flex strips / whatever you want to call them as you're looking at the panel ... for example slowly drag your finger nail over the surface of those film strips and look at the screen and see if there's some changes.

Mariush!!! Thanks. As you say, any of these are good reasons for failure of this LCD Monitor. And yes, this is beyond what I can do right now. Except moving my finger on the tape. Very interesting results. 1st time, the monitor screen seemed to flash light. At one strip the text (Dell Self Test) was all clear. Didn't hold. Deoxit on connectors seemed to help. Still had double images and garbled text. Thanks!!!

[rockblues]

One last question - the power stays on. Won't turn off. How to fix this? Some on the internet say use tape. Any answers here? Thanks.

And - what about this? Cleans electrical circuits. WD40 Company 300554 Specialist Contact Cleaner Spray - https://www.amazon.com/dp/B00AF0OFVU?

[Rasz]

were you doing it while monitor was on? and did the picture change at any point? this would mean its not the strips, Tcon chip and glass left

No. Monitor was off when I applied heat. Temp = 300C = Middle of the dial Tabiger variable soldering iron: 60W Temp Range: 200-450C

you are supposed to do the soldering iron over the strips with monitor turned on for immediate feedback
-either you locate spot where picture gets better, only this spot needs fixing
-or you cant locate such a spot, meaning strips are not the problem, and replacing tcon chip is the last resort

Except moving my finger on the tape. Very interesting results. 1st time, the monitor screen seemed to flash light. At one strip the text (Dell Self Test) was all clear.

-was it all clear and moving around? good
-or did screen flash and got undistorted for a split second before going blank? this means nothing
-or it froze during refresh, this is why its best to have something moving playing on the tv


You cant fix something without first diagnosing actual source of the problem. So far your efforts went in the opposite direction, replacing not broken things just because they were easy to get

[rockblues]

were you doing it while monitor was on? and did the picture change at any point? this would mean its not the strips, Tcon chip and glass left

No. Monitor was off when I applied heat. Temp = 300C = Middle of the dial Tabiger variable soldering iron: 60W Temp Range: 200-450C

you are supposed to do the soldering iron over the strips with monitor turned on for immediate feedback
-either you locate spot where picture gets better, only this spot needs fixing
-or you cant locate such a spot, meaning strips are not the problem, and replacing tcon chip is the last resort

OK. Thanks!!! Good to know.

Except moving my finger on the tape. Very interesting results. 1st time, the monitor screen seemed to flash light. At one strip the text (Dell Self Test) was all clear.

-was it all clear and moving around? good

Yes

-or did screen flash and got undistorted for a split second before going blank? this means nothing

It did this at first. Then after spraying DEOXIT on the ends of the ribbon connectors and on the connectors themselves, the flashing stopped.

-or it froze during refresh, this is why its best to have something moving playing on the tv

Very good point.

You cant fix something without first diagnosing actual source of the problem. So far your efforts went in the opposite direction, replacing not broken things just because they were easy to get

I agree. Replacing caps not broken - not needed. Overkill. Took 5 min. Just checking if there might be any improvement with higher quality Panasonic caps / greater voltage 35V vs 25V.

Tests I did that were valid -
- Using a replacement power board / main board - confirmed caps were not a problem
- Switching flat ribbons and using them with a replacement main board - told me ribbons / connectors were not the problem
- Spraying ribbon connectors with Deoxit cleaner - even rubbing them with a pencil eraser - helped a little - doing this corrected another bad LCD Screen with line problems (Tamil video)
- Running a finger over the strips - while monitor was on to see if lines stopped (did this 1st time) - double text box + garbled text + lines - still remained (Dell Self Test = only power on)

//////////////////////////////////////////////////////////////////////////////////////


Will try the heat on the strips with the monitor turned ON.

What about the monitor power on switch - always on?

Thanks.

[rockblues]

Found duct tape to make this monitor look like new - if I can ever get it fixed. No RF shielding. $1.49 for 2 IN X 10 YDS
And a new eraser for 99 cents. (Tamil Ribbon Connector Test)

[rockblues]

Just in case this might work - tried rubbing ribbon contacts with the new eraser. Dell Self Test = no improvement. Garbled text + double text boxes.

Paper bag under board enclosure keeping it raised and safe from making contact with panel chips.
Monitor powered on - no connection to PC - Ran the flat hot soldering iron 300C on each of the strips PCB contact area - dabbing a second or two - without tin foil - No tape melted. No change. Working left to right.
At the 3rd / 4th strip from the left, Top Text box became 100% clear!!!!!!! Double text box remained. As white box reached left screen edge, text became garbled again.

Would you apply more heat to the tape? What would you do?

[Rasz]

I would listen to myself and plug a signal into tv to see better what is going on
this box is moving around all the time, its possible there is position on the panel where one part becomes clear despite the defect
IMO it doesnt look like its the strips, you can try ordering that $12 chip

[rockblues]

... there is position on the panel where one part becomes clear despite the defect

Now I see what you mean. Took a photo of the Monitor hooked up to the PC with an HDMI cable.

IMO it doesnt look like its the strips, you can try ordering that $12 chip

Paused heating the strips to not damage them. Ordered the chip today.

Let's see if this chip makes a difference! Thanks!!

Arrived -

CIRCUITWORKS CW3220 NO CLEAN SOLDERING LIQUID FLUX LEAD FREE
https://www.ebay.com/itm/CIRCUITWORKS-CW3220-NO-CLEAN-SOLDERING-LIQUID-FLUX-LEAD-FREE-USA-seller/182592245714?

Arriving soon -

SMT SMD Component Welding Practice PCB Board Soldering Plate DIY Suite Kit -
https://www.ebay.com/itm/SMT-SMD-Component-Welding-Practice-PCB-Board-Soldering-Plate-DIY-Suite-Kit/163044288173?

Fast Chip Kit for Quik SMD Removal with a Low Temperature Alloy Arriving soon -
https://www.ebay.com/itm/Fast-Chip-Kit-for-Quik-SMD-Removal-with-a-Low-Temperature-Alloy/163808650408?

[rockblues]

Have practice circuit boards - SMD alloy - Flux - Chip!!! Need to practice this week, then do the real chip removal / install.

[rockblues]

Have all parts. Practiced adding. Then removing. Then adding an IC Chip to a test Practice board using plenty of flux. Anchoring diagonally opposing legs. Then swiping the legs of the chip with just enough solder to hold it to the board. Will remove the chip in place now with SMD Fast Chip. Lowers boiling point of solder so I can carefully remove the IC with tweezers. Clean up with SMD alloy with desolder wicking, then Isopropyl alcohol. If needed, will gently scrub area with fiberglass brush. Then solder new chip using lots of flux.

Showing the Chip I will replace and it's location in the monitor board.

[rockblues]

Replaced chip. Top side of the replaced chip kept oozing metal. Tried desoldering wick. Could not soak this up. Removed chip then added it back again. Upper left contacts gone from trying to desolder the oozing metal from the chip. Possibly this chip is applied with a suction cup and robot soldering. Why is metal oozing from top of chip? Thanks.

Saturday will reassemble the Monitor to see 1) does it explode 2) will it work or 3) is it permanently lost in the land of dead PCs!