I screwed up my Toshiba L355-S7905 by opening it: no more display on lcd

ok, first of all to my defense i've opened and replaced thermal paste and cleaned the fan assembly on a bunch of laptops before and never had an issue until this Toshiba L355-S7905. After I cleaned it and put it back, there was no picture on screen but connecting external monitor worked fine, also the backlight works fine, so I figured I should just reseat the lcd cable behind the screen (how that got affected is beyond me since all I opened was the lower part of the laptop). Anyway I reseat it, still no picture. I then bought two cables on ebay and still no picture with either one of them. Did the lcd module get screwed up somehow during the process? Its wierd cos my opening had nothing to do with it. any ideas on my next step?

 

did you remove the backup battery to see if that help. Sound like you for forgetting something.

 

I haven't messed with the bios battery (i think its on the bottom). just curious, how is it related

 

I would boot into Windows with an external monitor and try toggling the CRT/LCD function. If that doesn't work I would check for a pinched cable or a slightlycocked cable on the motherboard etc. You can also try loading your BIOS defaults to see if something got corrupted there as well.

One problem that can arise working on todays computers is that the manufacturers have switched to non lead solder so things can get stressed when working on them without you even knowing and problems occur.

 

I would concentrate my attention on where the cable from the display connects to the motherboard. I see from the photo that it is close to the fan and could have been disturbed. From what you say, you have tried a new cable or two in which case you need to look closely at where the socket is soldered to the board.

John

 

Sometimes when working with electronics removing all source power can help resetting everything back to default settings. Look like the lcd receives power and it is plugged to the mb from the picture. Remove the cmos battery, remove laptop battery and power plug. Press and hold power button for 30 seconds. Plug the laptop back to a power source and see if that help. If not you have to take everything apart and just try to power it on with ONLY lcd and ram, no internal or external usb. Nothing else.

 

I would take everything apart and reassble it again. That's the way I do if something doesn't work, just in case I have forgot anything..

 

just removed the motherboard to look underneath and the battery is soldered to the motherboard.

 

okay, then there must be a reset jump somewhere.

 

I was in to a BIOS issue on my X300 few years ago, and guess what? There isin't. Either a BIOS battery or reset jumper was to be found... Ended up by just leave it alone...

 

in that case, you would have two solder points where you can reset the bios. I forgot the name of it.

 

What makes you think resetting the BIOS has anything to do with his issue? IT IS AN OBVIOUS HARDWARE ISSUE.

You say you swapped LCD ribbon cable and still no go. Okay, then without an external monitor connected, shine a flashlight at an angle, and see if you can see anything on the screen. If you can see your desktop as normal using the flashlight, then the problem is the inverter.

 

ok, problem solved, when I plugged the lcd cable back in, some of the pin's inside the socket got bent. It was really hard to see, I'd to use a flashlight & magnifying glass to locate it lol. A good digital camera with macro zoom also helped lol. Unfortunately, I broke two pins while trying to make it straight. So, I'd to splice the lcd cable and solder two wires directly to the motherboard. I did a crappy job, so put a bunch of hot glue over it (i won't show you a picture of that lol). Anyway, I was super happy to get it working again.

Thanks to everyone with your support in making me not throw this laptop out the window

 

Done my fair share of dodgy wiring jobs - some of them still hold up after 4 years. Take care of your laptop from now on.