Thoughts on possible Dell Inspiron 1525 backlight/inverter issue

[calizza]

Here is the rundown. I will try to be thorough as possible.

I got in a Dell Inspiron 1525 laptop that when you use just battery power it worked fine. When it was plugged in the screen went dark (visible to flashlight).

I suspected it went dark when plugged in because of the power management settings turning the brightness all the way up when plugged in and dimmer when not.

I turned on the laptop with battery power, used the FN+arrow keys to brighten the LCD and sure enough it went dark when it hit the top brightness.

I tested the laptop with an external monitor and it worked fine.

I replaced the inverter. This resulted in the screen being dark no matter what the power settings were.

I then got a new LCD and replaced it (along with another inverter), again dark no matter the power settings. I tested the LCD in another laptop (inspiron 6000 the store said it was compatible). This resulted in a dark screen as well. I called the store and got a replacement shipped out to me.

I received the replacement screen and the exact same thing has happened including when tested on the other laptop.

My last thought is to replace the LCD ribbon cable though I think that may be grasping at straws since it did not work in either laptop.

I have installed the original inverter and screen back into the laptop but can not get it to go back to it's original issue. The screen is dark no matter what.

Am I looking over something?

 

[NYJimbo]

Just to be sure, did you try the original inverter with the new screen ?.

 

[calizza]

Yes I did try that.

I also just tried unplugging the inverter from the ribbon cable. This produced the same result. Does that point to a bad cable?

Just to be sure, did you try the original inverter with the new screen ?.

 

[NYJimbo]

Yes I did try that.

I also just tried unplugging the inverter from the ribbon cable. This produced the same result. Does that point to a bad cable?

On the first failure I would think its an old or dying CCFL which is pulling too much power from the inverter when turned up to full and thats turning off the inverter. But if you replace the whole LCD with the CCFL then that issue goes away.

I was thinking that you might have had some bad luck with the new inverters and just wanted to be sure you tried the original (or all) the inverters on the clients machine with the new LCD.

However, this very well could be a power issue on the motherboard. But since you cannot reproduce the original condition it is possible you have pushed whatever circuit is involved on the mobo to its breaking point.

If you can get an external image you might want to try to run Dell bootup diagnostics which can do alot of internal testing. Not sure if it will test the mobo's ability to fire the inverter, but at this point I have a feeling whatever was borderline before might be dead now.

btw- dont assume the LCD from a 1525 will work on a 6000, you can be adding other failures that are unrelated to the first systems problems.

 

[anonymous Mac Tech]

I also just tried unplugging the inverter from the ribbon cable. This produced the same result. Does that point to a bad cable?

Not very likely. Id say the next move is to try a new display and inverter in the good laptop first. Then maybe move those over to the flaky one with minimal other hardware to verify. If it is still doing it, maybe the machine is blowing out the LCD or inverter or both.

 

[calizza]

Thank you guys for the very quick responses.

I tried the new LCDs in the 6000 because the place of purchase stated this LCD was also compatible in that system. This was after I had already tried in the 1525.

I will try the Dell diagnostics and see how it goes.

Not very likely. Id say the next move is to try a new display and inverter in the good laptop first. Then maybe move those over to the flaky one with minimal other hardware to verify. If it is still doing it, maybe the machine is blowing out the LCD or inverter or both.

 

[NYJimbo]

Thank you guys for the very quick responses.

I tried the new LCDs in the 6000 because the place of purchase stated this LCD was also compatible in that system. This was after I had already tried in the 1525.

I will try the Dell diagnostics and see how it goes.

I know that the video chip and its related circuitry are responsible for enabling voltage to the inverter so like I said it could be something that may have failed completely.

Here is something interesting I have been checking out:

UNIVERSAL 5V INVERTER BOARD

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350289028839&ssPageName=STRK:MEWNX:IT

go down to the item description to check it out.

and this thing:

http://cgi.ebay.com/Backlight-Teste...tem&pt=LH_DefaultDomain_0&hash=item439ed420ce

 

[calizza]

I know that the video chip and its related circuitry are responsible for enabling voltage to the inverter so like I said it could be something that may have failed completely.

Here is something interesting I have been checking out:

UNIVERSAL 5V INVERTER BOARD


go down to the item description to check it out.

and this thing:

Very interesting, especially the second item.

 

[calizza]

Dell Diagnostic update...

During the Preboot system Assessment I came upon an error that indicates that it was unable to modify brightness. It gave me the error code 2000-0322 which when I looked it up says that it is an "Error accessing the LCD inverter".

During the custom diagnostic test I ran a cable detect test and it stated that it did find the LCD cable.

I ran the LCD Brightness test and I guess it further proved that it couldn't access the inverter.
"Exception occurred in module VIDEO.dm file "LCD.cpp" line 1009"

Once that hit it said to hit any key to return but once I did it came up with a full page of code and would not let me back to the testing screen to run more tests.

Once I get back to that point I will see if there are any more relevant tests to run.

 

[trapped]

This thing is a little pricey, http://www.lcdparts.net/LST01.aspx, but it works great for me.

 

[NYJimbo]

Dell Diagnostic update...

During the Preboot system Assessment I came upon an error that indicates that it was unable to modify brightness. It gave me the error code 2000-0322 which when I looked it up says that it is an "Error accessing the LCD inverter".

During the custom diagnostic test I ran a cable detect test and it stated that it did find the LCD cable.

I ran the LCD Brightness test and I guess it further proved that it couldn't access the inverter.
"Exception occurred in module VIDEO.dm file "LCD.cpp" line 1009"

Once that hit it said to hit any key to return but once I did it came up with a full page of code and would not let me back to the testing screen to run more tests.

Once I get back to that point I will see if there are any more relevant tests to run.

Wow, thanks for posting the results. I know it doesnt really help you that much, but for the rest of us we get to see what Dell diags would do in this situation. Very useful info.

You might want to get this tool (it takes about a minute to run after its installed) :

http://www.entechtaiwan.com/util/moninfo.shtm

and run it to see if it picks up the LCD data or the external monitor data. If it shows the LCD stuff then you can see if anything fails.

 

[calizza]

Wow, thanks for posting the results. I know it doesnt really help you that much, but for the rest of us we get to see what Dell diags would do in this situation. Very useful info.

You might want to get this tool (it takes about a minute to run after its installed) :

http://www.entechtaiwan.com/util/moninfo.shtm

and run it to see if it picks up the LCD data or the external monitor data. If it shows the LCD stuff then you can see if anything fails.

No problem, my intention is to try to post anything that I come across with this issue in case someone else could use the info. I know how frustrating it is to do searches and come up empty handed.

I will check out that tool later this evening when I get a chance, thanks!

 

[JRDtechnet]

Do you know if the screen when you received the laptop was the original screen? From experience Dell laptops are extremely picky on accepting LCD's the screens work fine but the brightness is always screwed up unless I get the same exact model screen. I bet the brightness controls are reversed for the new LCD screen, go into the system bios when your on battery so you can see and change the 'Brightness AC' setting to '1' instead of '8'. Also I've seen it where the darkness and brightness would alternate 1 would be bright, 2 dark, 3 bright, etc.

 

[calizza]

Wow, thanks for posting the results. I know it doesnt really help you that much, but for the rest of us we get to see what Dell diags would do in this situation. Very useful info.

You might want to get this tool (it takes about a minute to run after its installed) :

http://www.entechtaiwan.com/util/moninfo.shtm

and run it to see if it picks up the LCD data or the external monitor data. If it shows the LCD stuff then you can see if anything fails.

I ran the tool, it picked up the external monitor. I then just unplugged it and used the flashlight to see and ran it. Plugged the external back in and from what I can tell nothing failed. The one thing I saw I am not sure about is where it says power management it says Not supported.


BTW since I ordered the LCD ribbon cable before I had asked for suggestions on here I went ahead and changed it out anyway. Nothing different happened of course.

 

[calizza]

Do you know if the screen when you received the laptop was the original screen? From experience Dell laptops are extremely picky on accepting LCD's the screens work fine but the brightness is always screwed up unless I get the same exact model screen. I bet the brightness controls are reversed for the new LCD screen, go into the system bios when your on battery so you can see and change the 'Brightness AC' setting to '1' instead of '8'. Also I've seen it where the darkness and brightness would alternate 1 would be bright, 2 dark, 3 bright, etc.

The screen in the laptop when it came to me was the original Samsung branded.
The replacement is some knockoff but they swear they test them before shipment and I have received 2 of them.

I have used the original screen again as stated in a past response and the situation is the same.

I can no longer see the screen without a flashlight with or without the battery per my original post.

Also in the diagnostic results I posted that the inverter failed, would this setting still make a difference? I am thinking no but my thinking could be flawed.
I don't think I can see the screen well enough with a flashlight to navigate the bios.

EDIT: The external was able to show the bios. I changed the settings to no avail.

 

[calizza]

Unless There are more suggestions I believe I will be returning the laptop to the owner Monday and just eat the costs of the inverters and returning the LCDs.

I believe we have exhausted all resources except for changing out the mobo. I am leaning towards NYJimbo's theory of "However, this very well could be a power issue on the motherboard. But since you cannot reproduce the original condition it is possible you have pushed whatever circuit is involved on the mobo to its breaking point. "

I could suggest to change out the mobo but what if there are issues with the original screen? the cost of a new mobo, the LCD, and my labor they may as well just buy another laptop is what I am thinking.

Thanks to everyone's responses in this thread. Even if the issue hasn't been fixed I have come out with ideas of other things to check when something similar comes up as well as new tools to use.

 

[JRDtechnet]

Once last thing you should try, see if you can get the screen to light up by not plugging in the lvds cable to the LCD screen. Just have the cable plugged into the motherboard and inverter and then plug the backlight wire into the inverter. See if the screen lights up all in any senerio (AC, battery, play with the FN+arrows, etc). If it's still dark, try the screen on a non-dell laptop or at least just plug in the backlight to the inverter if the non-dell laptop doesn't have the correct connector for the lcd screen.

Also as a final hail Mary see if there's a bios update or if not try reloading the latest version who knows maybe something got corrupted and merely erasing and rewriting the bios will correct it...long shot I know but couldn't hurt.

 

[calizza]

Once last thing you should try, see if you can get the screen to light up by not plugging in the lvds cable to the LCD screen. Just have the cable plugged into the motherboard and inverter and then plug the backlight wire into the inverter. See if the screen lights up all in any senerio (AC, battery, play with the FN+arrows, etc). If it's still dark, try the screen on a non-dell laptop or at least just plug in the backlight to the inverter if the non-dell laptop doesn't have the correct connector for the lcd screen.

Also as a final hail Mary see if there's a bios update or if not try reloading the latest version who knows maybe something got corrupted and merely erasing and rewriting the bios will correct it...long shot I know but couldn't hurt.

Did all the above except the bios. I will check on that. Thanks