Page 1 of 1

W510 Backlight Fuses?

Posted: Sat Jan 03, 2015 9:10 pm
by Economizer
My W510 screen latch jammed and I cracked the screen just before the Christmas holidays. Although the machine is in warranty, I was traveling and did not have the box. I wanted to use the laptop heavily over the holidays, so I ordered a replacement LCD from eBay, paying far more than the cheapest for something that appeared to work:
item.ebay.com/400829700164

I mostly followed the Hardware Maintenance Manual instructions for removing the LCD assembly, until I realized that they were not appropriate for a simple screen repair. I then followed these instructions from an individual on YouTube:
https://www.youtube.com/watch?v=o4dKOf_28m0

The machine would not boot because while following the HMM I broke the ribbon cable. When I used a docking station to start the machine, the backlight was not working (I could faintly see "ThinkPad" on the BIOS splash screen and similar white text on my OS boot screen).

I reattached the old, broken LCD and its backlight was also dead.

Because the system is still under warranty, I received a new keyboard and LCD cable. The keyboard works, but still no backlight.

I think there might be fuses blown on the motherboard. Where are these fuses located on the W510, and are they replaceable?

Re: W510 Backlight Fuses?

Posted: Sat Jan 03, 2015 10:23 pm
by rkawakami
Sorry to hear about your repair woes, but I can answer your last question... I've not yet laid my eyes on a W510 motherboard, but I can say with some certainty that the fuse is not "replaceable" in the sense like an automotive fuse; i.e., pull out the broken one and push in a new one. All of the fuses I've seen on Thinkpad motherboards are surface mount types. That is to say, it's soldered down onto the motherboard. Assuming that the cause of the fuse blowing (if indeed that is your problem) is no longer present, then you can simply solder on the replacement right on top of the old one. It's typically easier to do it that way, instead of trying to remove the old fuse and soldering the new one in its place.

The fuse that protects the voltage driving the backlight is typically in the order of 0.5A and is usually located right around the LCD connector. You will be looking for something like one of these: http://forum.thinkpads.com/viewtopic.ph ... 93#p731793 Fuses are generally identified on the motherboard by a legend printed nearby that starts with "F" and has a number after it (e.g., F7). Some "fuses" are also 0 ohm resistors and could have a legend of R<number> instead.

If you have an ohmmeter, you can test the fuse by putting the meter in the lowest resistance range, and with the laptop off, put the leads on either end of the fuse. If the meter reads 0 ohms, the fuse is GOOD. If the meter reads anything above 0 ohms, the fuse is BAD.