No display on LCD intnl or xtrnl. Lid Switch?

Toshiba Satellite a105-s4134 notebook
January 22, 2010 at 04:58:35
Specs: Windows XP Pro w/ la, Pentium 4 w/ 1.8 ghz
So heres my problem. I'm working on a Satellite A105 for someone who said it was shutting off after awhile. I figured it was the cpu fan. I replace the fan and begin to put everything back together and just before snapping it all back up, I test to make sure all is well. Well the fan spun but I'm getting no display from the lcd screen. It's not dim, or doesnt ever flicker or come up for a second, just constant black. So I try to hook this thing up to an external monitor to see what I get and still nothing (I even hook up the keyboard and try FN + F5). Even after pulling off everything I could unplug (audio cables, touchpad, memory, keyboard, harddrive, wireless card, [didn't try the modem or pcmcia but thats it]) nothing changed. I'm not getting any beeps or any sounds either so I'm thinking I shorted the motherboard or something stupid. So I order a new motherboard and installed it... same problem.

Now I was very careful in the removal of the connector to the LCD screen but I haven't tested it (although it was working before I pulled it all apart even though that means next to nothing). But besides the actual screen was is there anything else this could be. I feel like I could order a new lcd cable or panel and it still won't work. How about the lid switch? This one is magnetic and the magnet is in the top right corner of the screen and I guess the switch is under the palm rest on the same circut board as the usb ports on the right side of the computer? I'll see if I can locate a similar machine to test the LCD screen on. Does anyone have any ideas? Any help is appreciated on this one.

Sorry for the long winded post.



See More: No display on LCD intnl or xtrnl. Lid Switch?

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January 22, 2010 at 05:18:33
You remove memory,theh power on your computer.If you hear the long bee sound,your maiboard has no problem.otherwise,buy one new maiboard.

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January 22, 2010 at 05:22:43
I said I removed the memory. I also removed the battery and have tested with just battery and just AC and no difference. I also said that I was getting no beeps whatsoever. Fans spin up and hard drive spins on and it seems like the machine is actually booting but I have no way of knowing.

And I also said I have purchased a new motherboard and am getting the same exact problem.

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January 23, 2010 at 20:38:42
Anybody have any thoughts on this? I still haven't resolved it. I've tested the inverter using a multimeter to see if I can get a Hz reading off of it and I don't get anything so my thoughts are 1) could be the inverter seems unlikely anything would've happened to it in the 2 or 3 days it sat apart from the machine because I never even opened the LCD panel, 2) the cable. I tested this with another cable/inverter combo I had to a bare CCFL and got nothing but I'm not too sure the inverters are compatible with each other. I also don't think it's this because of the fact that I was very careful removing it from the motherboard and same putting it back in. This finally leaves me with 3) the magnetic lid switch. The only component close enough to where the magnet in the display would come in contact with is the right, bottom side of the case which leads me to believe the sensor is built onto the wireless switch/usb PCB. I think replacing that is my next best option as I've ensured their connections were tight. It was the only thing that wasn't replaced with the motherboard. Has anyone ever even seen these fail (I'm sure its possible, but how likely)? Any other ideas or thoughts would be well appreciated.

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January 23, 2010 at 22:09:06
The ATX mboard on is always powered in some places, even when the computer is not running, as long as the main battery is connected and not completely discharged, and/or the AC adapter is connected and powering the laptop.
Did you have both the main battery and the AC adapter disconnected at all times when you were fiddling with unplugging / plugging in things inside the case, or plugging in or unplugging the ram?

NOTE that most if not all more recent laptops will NOT run on the AC adapter alone. The main battery has to be installed too, and be charged to at least a minimal capacity as well.
If the battery is not charged to at least a minimal capacity when it is by itself, or when the AC adapter is also connected, the computer will not start up, until the AC adapter has charged it to at least a minimal capacity.

How old is the main battery? People tend to neglect changing that. Typically they are able to be charged to their rated capacity for a year, then they begin to deteriorate (none of them have longer than a 1 year warranty, according to what I've encountered). By two years they typically can't be charged to anywhere near their rated capacity, and the older they get, the worse that situation gets. They often develop internal shorts when they are older - if so, when you attempt to charge them they get HOT rather than just warm, and they have been known to get hot enough to cause a fire. If they are internally shorted, when you measure it's voltage it may never get to it's full rated value.

Laptop no video on the LCD display, and battery / AC adapter / charging T - shooting.
See response 1:
In addtion to the possiblity the wiring to the LCD display is damaged, it could be shorting, which may fry the video adapter, or the mboard, or whatever.
The backlight is a CCFL - cold cathode flourescent lamp - I would think the voltage inverter supplies AC high voltage to it, just like for other flourescent lamps. Were you measuring AC or DC voltage? If the computer is not working properly otherwise, or if the baclight is failing which is quite common, no voltage from it may not be significant.

Similar to the power switch almost always not being the problem, there's probably nothing wrong with the lid switch, but you could try bypassing it (shorting across it) after opening up the case. Just don't fiddle with anything while power is connected to the laptop. In any case, the lid switch has no effect on the VGA port video output if there's nothing else wrong.

Does this laptop have a separate power module? If so, you haven't mentioned that - it could be damaged, although that seems to be very rare, unless you damaged it.

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January 24, 2010 at 08:48:23
Both power sources are disconnected before touching anything on the machine. I have also tested with just the AC adapter, just the battery and both. No difference. Battery holds a solid charge (although I'm not too sure on the numbers because I can't see them but I've run it for at least a half an hour).

When I tested the inverter, I used a non invasive method of setting my multimeter to Hz and measuring the frequency picked up the the two probes are held very close together hear the inverter. It wasn't powering anything so it picked up nothing. However, this only rules out its not the CCFL (I've tested it with the lamp unplugged, same thing). I'd like to test the AC or DC output but I'm afraid of the super high voltages of AC that is put out and I don't know the pinouts of the other connectors to measure DC into the inverter.

Power module wasn't touched until i swapped the new motherboard so I doubt this is the issue as well (it's connected via wires and not soldered onto the board; nice design btw).

Finally, I should be getting video externally lid closed or not, but Toshiba has this silly little program called FNesse which I believe everytime I hit FN + F5, I'm getting a software display on the screen asking me to choose an option.

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January 24, 2010 at 22:51:17
"Both power sources are disconnected before touching anything on the machine."


"I have also tested with just the AC adapter..."

As I said above most more recent laptops will not run on the AC adapter alone. I have friends who have a HP and a Compaq and neither will - they're about 4 and 5 years old.

Whether or not the voltage inverter works probably has nothing to do with the external VGA not working.
You can probably find info about testing that and the CCFL somewhere on the web, but as far as voltages go, there may be nothing to measure when the laptop isn't working properly - you may be able to do resistance measurements.

When I suggest that people try an external monitor when they have no display, if they respond, usually that works fine for them.

You should try to find info about how to test the power module on the web.

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January 24, 2010 at 23:24:59
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So big update. I rechecked craigslist and what do you know, someone had a a105 they were asking 150 bucks for it just didnt have a power adapter. I ran over and picked it up just before.

First thing I did was test what the lid switch does when the laptop is "closed" and I power it on. I should be getting the Toshiba post screen AND THEN it will go black. Also, if I connect a monitor, whether or not its enabled in the software, it will display to the monitor. This rules out the lid switch (I'll confirm it is located in the part I thought it was later).

Second thing I did was pull the screen off of the working laptop and hooked it up to my non working one. What do you know, no video. (I plugged it back into the working one and it came back up on that too. I also tested the original one, works as well.) So it's not related to the screen at all. Now at this point, I can probably just take the hard drive out of the non working and put it in the working and send it off but I want to get to the bottom of the problem here.

Now keep in mind, this is the second motherboard in the nonworking machine so it is likely another component attached to it that maybe I overlooked. Even the button switch which I can now test as well as the modem and pcimcia which I overlooked the first time around. Thanks for your help. I'll let you know what I find. Any thoughts, spit them.

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