Dell Insp2650 w/odd backlight behavior

[Tyrant774]

Hi everyone,

Well, I must admit I'm perplexed. I'm pretty computer-savvy, but not all that strong when it comes to laptops, and this problem has me scratching my head.

I'm currently using an Inspiron 2650 which has been nothing but kind to me since I purchased it early last year. Last November/December, however, it developed a backlight issue. I tried the usual troubleshooting steps before calling for service... every different power configuration you can imagine (battery/ac, battery/no ac, ac/no battery, remove battery and ac and cycle/hold down power, etc) but couldn't get the backlight to work. Naturally, tried an external monitor... worked just fine. Installed the most current BIOS rev... still no backlight. Called customer support, who was helpful and walked me through reseating the ribbon cable. Still no backlight. Stripped the 2650 of everything removable and sent it in for service, got at back and... beautiful! Backlight worked.

... Until I closed the lid and reopened it and woke it from standby the next day. No backlight again. Hesitant to call and send it off yet again for a problem that may not even be the backlight itself, I tried some more intensive troubleshooting on my own, and these are the trends I've noticed.

I have yet to get the backlight to work if I boot up with AC plugged in. However, if I remove the battery and cycle power a number of times or hold down the power button with no battery and no AC, or simply leave the battery out long enough, I can boot and get the Inspiron splash screen and the Windows XP bootup screen. However, once the bootup screen is done, the backlight shuts off at the logon screen. From there, with no backlight, I log in, and wait until I can faintly see my icons and know the OS is loaded. At THAT point, I can press Fn-F8 about ten times (actually, almost ten times EVERY time... I've counted)... and the backlight will come back on. At this point, once the backlight is on, there are NO more issues whatsoever. I can plug AC in and the backlight will stay on permanently (details coming). In fact, yesterday, I decided to leave for work with the laptop on AC power and see if the backlight stayed up all day. It did, and that was for a good 12 hours.

However, if ANYTHING shuts off the backlight, it's not coming back on. If it goes into standby, it's not coming back. If I shut the machine down, the backlight won't come on during the next reboot, unless I go through the remove power/cycle power button/boot/press Fn-F8 procedure again. This works pretty much EVERY time, and it's the ONLY way I've been able to get the backlight on.

This all leads me to believe that there may be no physical problem with the backlight itself. It isn't flaky or faulting at random times. During the bootup, it shuts off at the exact same time every time. I don't know enough about laptops to know what controls the backlight or power properties to do any more troubleshooting. I've gone to the BIOS and selected LCD Only there, but that doesn't change the behavior at all. (To be honest, I'm not even certain what the LCD/CRT/Simul selection there actually DOES.)

So, I've adjusted all the power properties to ensure that the system does not go into standby... once I have it up, I keep it up. Don't even think about closing the lid!

Most of the suggested solutions in this forum are to have the faulty backlight serviced (which I've already done) or to reseat the ribbon cable (done)... and I was looking for any other opinions, or wondering if anyone else has seen anything like this.

Just FYI, I'm running XP. I have the most recent BIOS rev (but during troubleshooting, I downgraded to an earlier to see if that worked... no good... reflashed back to newest rev), I have the most recent drivers for the GeForce2Go, and everything else is up to date AFAIK.

I'm really trying to think if I made any software or hardware changes before the initial backlight problems, but none come to mind.

If anyone has ANY ideas whatsoever, they'd be appreciated!

[VHockey86]

Well with all the troubeshooting and things you've done I hardly doubt its a software issue.

When you sent it in for service did they give you a report of what parts they replaced, etc?

Normally dell uses refurb parts for replacement parts.. so its possible you are just having really bad luck with the LCD.. but the fact taht you can get it to work via some sort of rsetting process sort of eliminates the LCD panel itself.

Perhaps the inverter cable between the card and the LCD panel is defective? About the only other hardware issue I can readily assume might be causing the problem (but like yourself I'm not much of a laptop expert either, so its kind of a guess).

[Tyrant774]

Thanks for the reply, VH. I concur that it isn't a software issue. When I recieved the unit back, it simply said the LCD was replaced, and (for whatever reason) the palm rest was replaced too. (Hey, I won't complain.) However, it does not go into any more detail and does not specify what an LCD replacement entails.

At this point, I'm pretty much convinced it's an inverter issue. I'm fairly certain the startup voltage delivered to the inverter is higher than it is once the OS is loaded, and that's likely why the backlight shuts down after the laptop posts and XP is booting. Like I said before, it's completely consistent.

Cycling between LCD/CRT most likely delivers a similar voltage, and sort of "wakes up" the backlight. Getting this to work, however, is not quite as consistent... sometimes it works, sometimes it doesn't. IMO, the inverter is probably just flaky and needs replacement.

The clock is ticking on my warranty coverage, though, so I'll need to place the call and get it back in for service. I'm really not looking forward to sitting on the phone and being asked to perform all the troubleshooting steps I already have, but oh well. =\

Thanks again!

[rockyglass]

Backlight Problem

I also have an Inspiron 2650, experiencing the exact same problems as Tyrant774. Whenever I close the lid, restart, shutdown, or hybernate, the backlight on my monitor goes out as well and cannot be restarted.

I cannot recall any changes made to the pc that would cause this backlight issue. Like Tyrant's computer, my problem was somewhat solved just as Tyrant's was. If you hit the FN key along with the F8 key at the same time, 10 times, the backlight comes on.

This is definitely a Dell problem, and not user error. If someone tells me "Dude, you're getting a Dell," I'm not interested. I believed they are designed to flaw after a year or two to encourage one to buy a newer model.