Studio 1735 Screen Lid Close Switch Location?

[AlaDes]

I have a Dell Studio 1735 that was brought in earlier this week. The problem is that the screen will only show a faint image when powered on. The customer had purchased another screen and inverter and tried installing them their self, but still the same result. I know the screen is good (tested it on a bench laptop), tried different known good inverters, and have even replaced the cable between the motherboard inverter and screen. The only thing I can think of it could be is the lid closed switch, which is what I am looking for. I have search google over and over and have browsed on Dell's forums but could not find any information on where the switch is located. Hopefully one of you has more experience with this model than I do and can direct me in the right place. Thanks!

 

[coffee]

Here is what I have done. I have a spare magnet that I took out of a junk laptop. When I am having problems finding the switch I take the magnet and slowly run it over the front of the laptop or the back by the hinges. Eventually the laptop will shutdown or the screen will shut off.

Another option I can think of would be to disassemble the screen area and look for the magnet that is installed in the laptop. This should give you an idea of where the switch is located.

Thats my .02c on the issue. Hope it helps a bit.

 

[JustInspired]

Wouldn't the switch put the laptop into sleep rather than turn off just the back light? Is the screen a LED one? If so it may be worth checking the fuse on the motherboard that is for the back light circuit.
Regards, Julian

 

[NYJimbo]

I hate to tell you to do the stupid BIOS reset thing but do the stupid BIOS reset thing. Many Dell laptops have a setting in the BIOS where you can tell it what level to put the brightness at. If you haven't also try the FN+Whatever keys that make it brighter or darker after it boots up to windows.

Its just a couple of easy things that might produce something before you go in deeper.

EDIT: Also very closely inspect the motherboard LCD cable connector. Sometimes people will force it and break a few solder joints or crush something when they reconnect a cable and you won't suspect it because you don't think they would jam it in (but they do).

 

[AlaDes]

Here is what I have done. I have a spare magnet that I took out of a junk laptop. When I am having problems finding the switch I take the magnet and slowly run it over the front of the laptop or the back by the hinges. Eventually the laptop will shutdown or the screen will shut off.

Another option I can think of would be to disassemble the screen area and look for the magnet that is installed in the laptop. This should give you an idea of where the switch is located.

Thats my .02c on the issue. Hope it helps a bit.

I have already disassembled the screen (actually the client brought it in already dissasembled) and cannot locate a magnet anywhere.

Wouldn't the switch put the laptop into sleep rather than turn off just the back light? Is the screen a LED one? If so it may be worth checking the fuse on the motherboard that is for the back light circuit.
Regards, Julian

I thought the switch turn the screen off completely until I ran into some other posts regarding the lid switch being stuck and causing a dimming problem versus all the way off. This is an LCD screen. As far as the fuse goes...Do you have any idea where a fuse that controls the backlight might be located?

I hate to tell you to do the stupid BIOS reset thing but do the stupid BIOS reset thing. Many Dell laptops have a setting in the BIOS where you can tell it what level to put the brightness at. If you haven't also try the FN+Whatever keys that make it brighter or darker after it boots up to windows.

Its just a couple of easy things that might produce something before you go in deeper.

EDIT: Also very closely inspect the motherboard LCD cable connector. Sometimes people will force it and break a few solder joints or crush something when they reconnect a cable and you won't suspect it because you don't think they would jam it in (but they do).

Using an external monitor, I have tried the BIOS settings and they are all the way to the brightest setting. I have even gone into Windows and changed the lid closed setting to where it never goes off. As far as the LCD connector, I purchased a brand new one because I knew the screen was good by testing it on a bench laptop.

Thanks for everyone's help. I am very grateful for all the responses. I did speak to the client today and she informed me that just befor the screen went completely dim, the laptop screen would not go out when she closed the lid, which is still causing me to lean towards the lid switch being bad. Just locating the darn thing is a pain lol.

 

[AlaDes]

Update

After looking at the frame that snaps into the laptop lid, I located the magnet for the lid closed switch. I actually forgot that's where they are usually located due to the client already having the screen dissasembled lol. It seems that the lid switch is functioning fine, as it switches from the laptop screen to the external monitor when I apply the magnet to the switch (turns the laptop screen completely off), which is located near the mouse. Any other ideas? I wouldn't think this would be a graphics chip problem due to the fact that the only thing wrong with it is the dimming issue.

 

[AlaDes]

Resolved

I thought I would check back in and let you all know that I finally found the problem. It was a ground and inverter issue. The client that owns this laptop had already purchased a new screen and inverter before bringing it to me.

Not thinking a new inverter would be bad and trying the old inverter as well, I decided to use what I know from working with electrical issues in automobiles and knew it had to be a ground related issue.

Taking out all the parts the client had purchased and replacing them with the original parts, the laptop screen was still dim. I pulled out the inverter and examined it closely and noticed that the grounding pad was being covered by the clear plastic and could not get a good connection, so I partially removed a small piece of it to expose the grounding pad. I reconnected the inverter, powered the unit on, and the screen lit up! However, after booting into the OS, the screen went dim after about 3 minutes. With the unit still on, I began slowly turning the small grounding screw holding the inverter in place and the screen flickered on and off. I powered the unit off, ran a separate ground wire and booted the system again to find out the same thing happened: after about 3 minutes the back light could go dim and If I turned the grounding screw it would come on again and go back off.

Not having much to do yesterday and loving to figure problems out, I decided to do some experimenting with what I knew was a bad inverter, as the client had originally expected. They just happened to get another bad inverter when they ordered a replacement.

Knowing the inverter would work if the ground screw was turned and that this was a ground issue, I knew it had to be internal to the inverter because I had already ran ground straps and they wouldn't work. So, I broke out my hot air station (which actually worked this time) and began re-flowing the inverter. After allowing it to cool for a few minutes, I reconnected it back to the laptop, booted it up, and allowed it to sit for a few minutes. It actually stayed on for over 3 minutes. The laptop has been on for almost 24 hours now and hasn't went dim yet. So, I've already got a new inverter on the way.

 

[EmpireDigitalTech]

Glad you figured it out, I was leaning towards the inverter being bad as well, usually people order the cheapest parts online and in return they get used or broken parts. You get what you pay for.

 

[NYJimbo]

Not thinking a new inverter would be bad and trying the old inverter as well, I decided to use what I know from working with electrical issues in automobiles and knew it had to be a ground related issue.

Some laptops seem to have no visible grounding of anything and others have at least one for the LCD cable or even more. I think we had a Lenovo a couple weeks ago with 3 or 4 different ground straps throughout the laptop.

Lack of ground either from a strap or a broken circuit can do all sorts of problems and like what you went through and can take a long time to isolate.

I wish it was easier, I mean we don't get paid more in these situations.