T410i won't boot (no beep, power LED on, LCD blank) (2518F5U)

[scootley]

Hi,

I have a T410i model 2518F5U. It will not boot.
When hitting the power button, the ring around the power button does illuminate and stay on, but the LCD never turns on. The mic and speaker on/off LEDs come on for a second, as does the Bluetooth LED and the Caps Lock LED, and the LED on top of the display that lights up the keyboard form above also comes on briefly

The fan spins for about 10 seconds and then shuts off. There are no beeps.

I am somewhat experienced with laptop hardware repair/diagnosis. I have already replaced the motherboard and the CPU and still these symptoms persist, which baffles me. I have tried booting with various components detached such as the main battery, motherboard battery, RAM, HDD, CDROM, Wifi card, modem card, keyboard, top cover (trackpad+BT+fingerprint), LCD main cable, LCD second cable (webcam?), speakers, IO subcard (USB,1394,modem jack). But there are so many possible combinations of which components to try removing at once that I am not sure which to try.

I have tried booting with an external VGA monitor attached and nothing shows up on it.
I have not yet done any disassembly of the LCD.

When the laptop was working (with all components as shipped from factory), it was dropped by about 2 feet and afterwards it booted fine but ran very slow (although it was a bit clunky before the drop as well). I added RAM and replaced the HDD (which was failing) with an SSD, and it booted ok for a short time but then started to exhibit the above symptoms when attempting to reboot. A few tries at rebooting would ultimately work but after a few more days it would never boot.

Any ideas?

Thanks

[RealBlackStuff]

Welcome to the forum.
Replacing the mobo is rather drastic.
If that did not solve the problem, something else is wrong/broken.
The fall might have disconnected the LCD cable on the back of the LCD.
That could have blown 1 or more fuses.
Check all fuses around the mobo LCD-connector.
Disconnect LCD cable from mobo, then try external monitor again.
Have you tried another keyboard?

[scootley]

Welcome to the forum. ...

Thanks @RealBlackStuff.
Yes replacing the mobo was drastic but I am trying to get it fixed in a rush. The replacement mobo is from eBay and is used so I hope I am not so unlucky that it has the same issue as the original has (whatever that might be)

I guess there are 3 LCD-related fuses I see at first glance here: http://thinkwiki.de/T410_Sicherungen
But since I replaced the mobo I haven't checked them on either the old or new one yet.

The LCD cable on the back of the LCD (which I have now opened) seems connected just fine.

I tried another keyboard and it doesn't help.

To your suggestion of trying an external monitor with LCD disconnected - any tips on which of these components need to be connected for me to be able to boot to BIOS:

1. main battery
2. motherboard battery
3. RAM
4. HDD
5. CDROM
6. Wifi card
7. modem card
8. keyboard {assuming yes}
9. top cover (trackpad+BT+fingerprint)
10. LCD main cable (actual display connector)
11. LCD second cable (webcam + keyboard light + lid switch + wifi/BT/HDD LEDs + mics)
12. speakers
13. IO subcard (USB,1394,modem jack)

[scootley]

I tested on another working T410 (not quite the same sub-model) and I can say that these components do not need to be connected to boot:
1. main battery
2. motherboard battery
4. HDD
5. CDROM
10. LCD main cable (actual display connector)
11. LCD second cable (webcam + keyboard light + lid switch + wifi/BT/HDD LEDs + mics)
13. IO subcard (USB,1394,modem jack)

And this one is needed:
3. RAM

Not sure about the other 5 components I mentioned in the previous post and which are actually required to boot.

However, if the LCD is disconnected then an external display must be attached to verify that the boot sequence/BIOS worked, and in order to see anything on that display (VGA), I had to hit Fn+F7. If you don't use that key combination then you will never see anything.

That helps me try more tests on the machine that is not working, but I still haven't figured out what is wrong with it and its behavior is still as I described in the OP

[RealBlackStuff]

You need to test with this minimum if motherboard is outside:
- RAM
- keyboard
- fan
- CMOS battery
- [speakers optional/if possible]
- charger
- external monitor
Test-1:
Try to boot and immediately hit F1 a few times to go into BIOS
Try to get the monitor to work (Fn/F7)
If the motherboard is OK, you should have a BIOS picture.
Switch off.

Disconnect monitor and connect only LCD-display-cable.
Test-2:
Try to boot and immediately hit F1 a few times to go into BIOS
Try to get the LCD to work (Fn/F7)
If the LCD stays dark, get a flashlight and check if you see a picture in the background.
If yes, your backlight fuse (or the backlight itself) is shot.
If no, switch off, remove/reattach the LCD cable from the back of the LCD.
Go back to Test-2:

Any luck?

[scootley]

Thanks. I tried the below tests with the motherboard still physically in the magnesium frame and that frame within the "base cover" (bottom plastic case) so that I could ensure the fan is mounted correctly, but otherwise with only the items you mention electrically attached.

Test-1:

Nothing ever shows up on the external monitor for Test-1

Test-2:

Nothing ever shows up on the LCD for Test-2. Separately, I actually connected the LCD to the mobo of that other working T410 that I have and it works there just fine, so I don't think there is any issue with the actual backlight or the cable connection on the back of the LCD.

I also tested the RAM in the other working T410 and it is fine. Keyboard and charger are known to be ok. Fan spins (temporarily). CMOS battery doesn't seem to be required but I also haven't tried voltage testing it.

So here are the possibilities that I can think of:
1) The eBay replacement mobo that I got is not operational (this is my suspicion)
2) I attached the CPU to the mobo incorrectly
3) Something about the way the mobo is physically mounted into the frame/case/heat sink is causing a problem

[RealBlackStuff]

Keep LCD and speakers connected, remove RAM, battery, charger and CMOS-battery.
Press the power-on key and hold it down for ca. 20 seconds to reset/discharge the motherboard.
Reconnect only the charger and try to boot, it should beep 1-3-3-1, assuming the speakers are OK.
If no beep, then you have a dead motherboard, return it for a refund/replacement.

What happens if you do the above with the old mobo?

[scootley]

... it should beep 1-3-3-1, assuming the speakers are OK.
If no beep, then you have a dead motherboard ...
What happens if you do the above with the old mobo?

No beep. I will try with the original mobo later. Thanks.

[scootley]

What happens if you do the above with the old mobo?

Well I tried with the old mobo and it gave the 1-3-3-1 beeps.
So I decided to do a part-by-part reassembly with the old mobo and old CPU where I booted the machine after attaching each part.
And amazingly, no part (except one) seemed to stop it from booting, and so now it actually fully boots the OS.
But the one part that causes an issue is the battery. If I connect the original battery to the back, the system will not boot.
If I connect another working Thinkpad battery, it seems to boot fine.

[RealBlackStuff]

Your battery must be the big sinner then, ditch it.

You mean to say you bought a replacement mobo AND a CPU? What a waste...
What does the new mobo do with the old CPU?

[scootley]

You mean to say you bought a replacement mobo AND a CPU? What a waste...
What does the new mobo do with the old CPU?

Yes luckily I ended up paying only $20 for the new mobo+CPU so not a huge waste of money but definitely consumed a lot of time.
I had actually replaced only the mobo first and left the original CPU, which did not boot. Then later was when I replaced the CPU as well.

So in the end it is really a mystery because I had certainly tried the same configuration of components that ended up working (i.e. without battery).
Maybe there is some sort of weak connection somewhere that could crop up again but that I managed to fix by taking it apart so many times.

Thanks for the help!

[RealBlackStuff]

You're welcome!
Check that the working battery charges!

Next time, begin with:
Keep LCD and speakers connected, remove RAM, battery, charger and CMOS-battery. Also CD and HD/SSD.
Press the power-on key and hold it down for ca. 20 seconds to reset/discharge the motherboard.
Reconnect only the charger and try to boot, it should beep 1-3-3-1, assuming the speakers are OK.