CCFL to LED conversion where inverter is integrated into the power board

[Snood McGuinness]

Hello there,

A coupla days ago I got the 2 seconds to black issue, and after troubleshooting for a while, I found out that the issue is a bad CCFL. When removed and powered up, the tube glows a bright red before cutting out.

Correct me if I'm wrong but I could not find any financially viable CCFL replacements, and have decided that the little CCFL to LED upgrade kits are the way to go. However, upon looking at the board, I see that the inverter is actually integrated into the power board (see pictures). Is there any way to perform the backlight change process without the handy 6 pin header that the LED drivers plug into? I would be happy soldering into the board if I needed to solder into specific places.

Please help, I would rather not fork out for a new monitor.

Thanks in advance,

Sam

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

you remove the cfl connectors, blue caps and 2 transformers,
use that area to mount the led driver.

on the underside you will find the gnd, 12-18v and the lamp & dim signals.
they are often labeled for servicing.
i think i see the lamp-on signal on the white connector - lower right.
you can get the supply power from the cap below the invertor transformers.

one thing i see, you need to resolder the mains inlet connector and stuff mounted on heatsinks.

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

Speaking of these CCFL to LED retrofits, have people found them to work well or do they leave much to be desired? How about IPS displays with their brighter backlight needs?

[Snood McGuinness]

Re: CCFL to LED conversion where inverter is integrated into the power board

you remove the cfl connectors, blue caps and 2 transformers,
use that area to mount the led driver.

on the underside you will find the gnd, 12-18v and the lamp & dim signals.
they are often labeled for servicing.
i think i see the lamp-on signal on the white connector - lower right.
you can get the supply power from the cap below the invertor transformers.

one thing i see, you need to resolder the mains inlet connector and stuff mounted on heatsinks.

Sorry if I'm being slow but I would just like to check.

So unsolder all the components I've circled in blue,
Solder the power to the positive side of the capacitor (circled red)
Solder the ground to any contact marked ground?
I cant see any lamp or dim labels on the board at all. Are these 100% necessary and if so is there any way I can find the contacts?

And I should resolder the three connectors to the mains inlet (circled black). What do you mean the stuff mounted to the heatsinks?

Sorry for all the questions and thanks for your quick reply!

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

your diagram is correct.
and you dont need the diming signal.

i marked the other stuff.
on the lower foto, those joints dont look good - but the picture is not great either.

on the upper foto, can you take another of just that area where i can read the writing?

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

Speaking of these CCFL to LED retrofits, have people found them to work well or do they leave much to be desired? How about IPS displays with their brighter backlight needs?

no idea about IPS, i'v not seen anything that new fail yet.

as for the kits - do a search - another forum member fitted one for a review.

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

Interesting. I have an IPS LCD monitor that I destroyed the inverter in during a recap, unsure why (probably due to a bad connection to the CCFL) and was thinking about converting to LED if I can't fix the CCFL driver.

The thing is that it has three CCFL tubes in it, and all the kits I've seen are two bulb... Maybe the IPS monitor already compensated by adding another tube...

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

3 tubes?
how are they mounted - all together or top, mid, bottom?

i'v seen 6tube rigs - got a tv like that.
3 tubes all together at the top, 3together at the bottom.

the last kit i fitted, LG tv.
the tv had 2tubes together at the top and 2 tubes together at the bottom.
i fitted a single led strip at the top and a single strip at the bottom.
the brightness was o.k.

i cant say if it was better or worse because it never worked with the tubes when i got it anyway.
that was well over a year ago, customer uses it for about 16hours a day in his kitchen and it's still going strong.

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

I haven't pulled the tubes yet but I would assume top/middle/bottom as other combos probably wouldn't be as uniform brightness - which is what I'm most worried about going to LED. I'm kind of miffed that the driver leaked out the magic smoke after I recapped it and tried to test it the first time. I tried putting a new transistor in for the one that leaked smoke but it still wouldn't work, hence the possibility of just throwing it all away and LEDing it.

Sorry about the hijack, but it too has CCFL driver integrated into the power board, so likely i'll have to disconnect the CCFL power and reroute to the LED power as well...

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

you can usually tell the tube location by where the cable goes into the panel.

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

And that I did not really look into yet Though I recall them being separated considerably leading to the three equally spaced tubes.

I also wonder about these LEDs whether the size they mention is diagonal screen size or length of the strips? The monitor I'm thinking about retrofitting I think is a 20.5-21" 5x4 IPS ... tubes are 16" wide. A 21" 16x9 would have longer tubes...

[budm]

Re: CCFL to LED conversion where inverter is integrated into the power board

I doubt that it has three tubes, you can tell by the amount of the two-pin lamp connector you have.

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

led kits are listed by strip length.
so check the length of your tubes before ordering!

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

Okay, because I've seen some kits say "for 17" monitor" which is kind of deceiving.

This thing DOES have three tubes - there are 6 2-pin connectors.

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

I guess the other thing is that it indeed is 5x4 - so the height is fairly tall compared to other LCDs and thus may need more tubes. A 21" 5x4 is 13.19 inches tall by 16.40 inches wide (calculated), plus this is a dimmer IPS panel. A 19" 16x9 panel would be 9.31 by 16.56 inches, so I would assume a 19" panel CCFL would just about fit in the 21" 5x4 ... but that's width. Height, the 21" 5x4 is almost 4 inches taller despite only 2 inches diagonal measurement increase.

That's why I gotta make sure, fleabay retrofit kits are showing monitor diagonal size in inches and then later strip length deep within the description.

Is there a better place to acquire these than fleabay?

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

there are 6 2-pin connectors.

then it has 6 tubes.

question is: are they in 2 groups top/bottom or left/right,
or are they spread equally behind it!!!

[Snood McGuinness]

Re: CCFL to LED conversion where inverter is integrated into the power board

your diagram is correct.
and you dont need the diming signal.

i marked the other stuff.
on the lower foto, those joints dont look good - but the picture is not great either.

on the upper foto, can you take another of just that area where i can read the writing?

Yeah, sure, I've attached it. Do you think it would be the inv_on for the lamp signal?

[stj]

Re: CCFL to LED conversion where inverter is integrated into the power board

inv_on is definatly the lamp control
12v is probably linked to the big cap,
brt may be the dimming signal.
but that often wont work because there are several ways to ajust brightness.

[eccerr0r]

Re: CCFL to LED conversion where inverter is integrated into the power board

then it has 6 tubes.

question is: are they in 2 groups top/bottom or left/right,
or are they spread equally behind it!!!

woah... is that normal for a mere 21" LCD? I guess it is then two groups of three on top/bottom. Without disassembling further it looks like there are 6 transformers on the inverter board that leave in two pairs of two connectors - one 2-pin and one 4-pin on both top and bottom - so a total of 12 wires leave - six on top and six on bottom. As far as I can tell the wires go to two sets of (SEVEN?) wires along one of the shorter sides which corresponds to 2 sets of three tubes?

I'd need to blow away quite a bit of the circuitry or at least figure out where to cut the PCB to disable the CCFL driver, but need to make sure the rest of the monitor is still working before I proceed further.

[budm]

Re: CCFL to LED conversion where inverter is integrated into the power board

Some of the GATEWAY, Viewsonic, and DeLL 21" or larger I repair has 3 tubes on top edge, 3 tubes on bottom edge.