T420 Running Hot?

[gfuller]

I've got everything reassembled, but we have some bad news:

I put the battery in to test, and nothing. I pressed the power button, and it just blinks green every second. I'm not sure what is happening... any advice?

No BIOS screen, nothing. Screen stays black. The DVD drive does spin like it does on startup, but that and the blinking green power LED is the only activity. The screen backlight isn't even illuminating.

I did not unplug the CMOS battery during disassembly. I'm so worried I may have fudged something up, like shorting something out or damage the CPU.

Edit: I plugged in the laptop. While it still continues to only blink the green power LED (no backlight, doesn't seem to pass POST, and no BIOS screen or anything), the battery LED on the lid does illuminate when AC power is connected.

Edit #2: I took the keyboard off to make sure everything was tight. Everything is tight and looks like it did before. When powered up, the fan doesn't even move an inch.

[Thinkpad4by3]

Did you upgrade the CPU yet? Some of them require a pin mod or they refuse to boot.

[gfuller]

Did you upgrade the CPU yet? Some of them require a pin mod or they refuse to boot.

I wasn't going to upgrade the CPU. I just removed it, as I thought that I was going to need to remove the magnesium frame to gain access to the screw. The CPU went back in and I made sure to "lock" it.

I now have pictures.

Before "total" disassembly:
http://personal.garrettfuller.org/blog/ ... 11_web.jpg

This is the heatsink before:
http://personal.garrettfuller.org/blog/ ... 37_web.jpg

After I applied new thermal grease. Did I apply too little or too much? I tried to apply as little as possible (I read somewhere a grain of rice sized drop) but this was as little as possible. The old grease was cleaned off the CPU, GPU, and heatsinks using 70% alcohol.

http://personal.garrettfuller.org/blog/ ... 55_web.jpg

Still kind of upset/ashamed at myself that it didn't work when I reassembled it. As mentioned, I've reassembled other computers before and not a single problem. Since I'm going into computer information systems (CIS - I'm in college), it's even more frustrating.

Screws have always given me problems. I've tried and tried to keep my screws separated by size, but my systems rarely work and here we are. I also have fat fingers that make it difficult to work with the small screws that this laptop has.

I have to return to school, so I'm letting my cousin who is also into computers fix it.

[Thinkpad4by3]

Did you accidentally bend a pin?

[gfuller]

Did you accidentally bend a pin?

Shouldn't have. I didn't use much force to push it in, if any. IIRC, it slid right in easily.

[Thinkpad4by3]

Yep, you have a November 2011 machine. It is a EEPROM Systemboard failure.

"Lenovo has identified an issue which affects a portion of Think and Idea systems that were manufactured between September and December 2011. The issue manifests as early life failures of the EEPROM chip and results in the system failing to power on or boot up. Not all of the systems manufactured during this period of time are affected. This is an industry component issue and is not limited to Lenovo.



The solution is to replace the system board, Lenovo has been working through an unanticipated increase in demand for system boards and some repair times have been longer than desired. Lenovo's parts logistics teams have worked closely with suppliers to accelerate availability of replacement boards and service part stocks have been updated with the latest level parts.



Service times are beginning to recover. Where possible, Lenovo is proactively escalating aged customer repairs to ensure resolution as quickly as possible. We apologize for any inconvenience these delays may have caused."

[gfuller]

Yep, you have a November 2011 machine. It is a EEPROM Systemboard failure.

"Lenovo has identified an issue which affects a portion of Think and Idea systems that were manufactured between September and December 2011. The issue manifests as early life failures of the EEPROM chip and results in the system failing to power on or boot up. Not all of the systems manufactured during this period of time are affected. This is an industry component issue and is not limited to Lenovo.



The solution is to replace the system board, Lenovo has been working through an unanticipated increase in demand for system boards and some repair times have been longer than desired. Lenovo's parts logistics teams have worked closely with suppliers to accelerate availability of replacement boards and service part stocks have been updated with the latest level parts.



Service times are beginning to recover. Where possible, Lenovo is proactively escalating aged customer repairs to ensure resolution as quickly as possible. We apologize for any inconvenience these delays may have caused."

What does that mean? How can I/my cousin repair it?

It worked just fine before disassembly. Did I do something wrong, except for possibly mixing screws up and getting the wrong screws in the wrong places?

[Thinkpad4by3]

Basically the EEPROM is a little chip that contains the BIOS to boot the machine. Unless your cousin has some pretty serious gear to reprogram it. One thing you can try before going to get a new systemboard is to take out the AC adapter and battery and hold the power button for 30 seconds. Then attempt to turn it on. Anything could have made the EEPROM go haywire, a tiny static shock, a little piece of dust, you just don't know.

[gfuller]

Basically the EEPROM is a little chip that contains the BIOS to boot the machine. Unless your cousin has some pretty serious gear to reprogram it. One thing you can try before going to get a new systemboard is to take out the AC adapter and battery and hold the power button for 30 seconds. Then attempt to turn it on. Anything could have made the EEPROM go haywire, a tiny static shock, a little piece of dust, you just don't know.

I know the EEPROM is what contains the BIOS, but I didn't know Lenovo was having problems with it. I was trying to take as much anti-static precautions as possible, but I had to end up working on a towel.

How much would a replacement system board cost?

[Thinkpad4by3]

25-30$ plus ship.

Make sure to check your FRUs before buying.

[gfuller]

25-30$ plus ship.

Make sure to check your FRUs before buying.

I'm going to e-mail my cousin a link to this thread.

[gfuller]

Okay. I heard back from my cousin earlier this evening on the T420.

He got the blinking light issue fixed. He said it seems to be booting and passing BIOS, so we're good there.

The problem is there is no back-light on the monitor. He says it doesn't even blink. He checked the connections and everything is tight and proper. The ThinkLight even illuminates, which further implies that there isn't a loose connection somewhere.

I can recall being cautious to reroute the monitor wires properly, and trying to keep everything routed as it was prior to disassembly. Of course, with the wireless LAN and speaker wires that was extremely difficult to manage. (Especially with the speaker wires and the strange path.)

Any thoughts? Of course, the primary thing that comes to mind is a bad LCD (highly unlikely as it was working before) or a bad wire/connector (again, unlikely, but more likely than a bad LCD.)

Is the right connector (the one on the right top side of the system board) for backlight power and possibly power for the LEDs and ThinkLight, and the left connector for monitor data and webcam? If so, could the problem lie in the data/webcam connector (which may prevent the backlight in the LCD from turning on) while the ThinkLight is getting its power through the right (power?) connector and is controlled directly on the system board rather than communicating with another board in the top case?

I guess another test would be connect an external monitor to its VGA output and see if the monitor responds. While it likely won't respond (?) until the system hands control over to Win10, it should eventually get there if nothing is halting it.

Any help is greatly appreciated. I'm making progress and this has been a great (and valuable) learning experience. It pays to be hands-on, as now I know what I need to improve on in the future.

It's also good to know that the BIOS EEPROM isn't toast. From what I can find (by looking at component date codes from my pictures) this machine was likely manufactured in early (January or February) 2012.

[jaspen-meyer]

You've already gotten the correct screw drivers. But, it's worth mentioning: the key to screw drivers is to have one which fits the screw. If the fit isn't snug, wait to get the correct screw driver. Your probability of stripping a screw is 40x higher if you're using the wrong screw driver -- and stripped screw heads are a real hassle.

[gfuller]

You've already gotten the correct screw drivers. But, it's worth mentioning: the key to screw drivers is to have one which fits the screw. If the fit isn't snug, wait to get the correct screw driver. Your probability of stripping a screw is 40x higher if you're using the wrong screw driver -- and stripped screw heads are a real hassle.

I understand - and that's why I paid ~$18 for a pair of correct screwdrivers (#0 and #00) from my local Ace Hardware store.

I should also mention that I used the flathead (standard) screwdriver to get some of the phillips-style screws out. I found that for some of the screws, that actually worked much better than using the screwdriver.

In the end, I only stripped two or three of the screws. The main problem was getting the right screws in the right places, and then making sure not to drop them (I have fat fingers.) In the future, I should do a better job of separating the screws and diagramming where each type of screw goes. (Thankfully, I think the service guide on Lenovo's website lists each type of screw size and where they go for the most part.)

[Thinkpad4by3]

I should also mention that I used the flathead (standard) screwdriver to get some of the phillips-style screws out. I found that for some of the screws, that actually worked much better than using the screwdriver.

My main driver bit is actually a 2.5mm flathead. THen I'll go over to the #0 or #00 phillips head.

[gfuller]

Okay. Got some more information.

As mentioned one of my previous posts, my cousin said that the computer appears to be booting and POSTing. He mentioned that the ThinkLight illuminated, and the power LED no longer blinks.

However, no video output. No LCD backlight or anything - although it clearly is getting power up there.

I asked him to plug an external monitor into the VGA port and he said na-da. Nothing happened. So at least now we know that the LCD and its cables are not at fault.

So, what should I/we check now? My cousin thinks the lid switch is bad or isn't being activated, which could be the culprit if the lid wasn't fastened properly. (Though the lid seems to open/close tightly.) The lid switch was working properly before (although from time to time the computer wouldn't go to sleep when lid was closed) the disassembly process, so I'm don't think the switch just coincidentally failed. (That and switches rarely fail.)

Any ideas?

[RealBlackStuff]

Looking at prices on eBay I'd say get another motherboard, rather than wasting more time on it.
Less than $20: https://www.ebay.com/itm/182601858284

[gfuller]

It appears to be booting, it's just there is no video. I'd like to check the lid sensor before going through the hassle of replacing a system board that may not be faulty.

I am trying my hardest to avoid digging further and removing the magnesium frame, because that looks somewhat complicated. My cousin doesn't really have the time to mess with it any further, and to be honest my time is limited as well. But I also need to get it fixed as it is my daily driver/main machine.

[axur-delmeria]

Try disconnecting the LCD cables from the system board end, attach an external monitor, then turn on the laptop.

If you still don't see anything, something is really wrong with that board.

[gfuller]

Try disconnecting the LCD cables from the system board end, attach an external monitor, then turn on the laptop.

If you still don't see anything, something is really wrong with that board.

So disconnect the LCD cables and plug in an external monitor to the VGA port on the side and see if anything comes up?

What about the lid switch? Where is the lid switch even at? In the socket where the screen hinge mates with the chassis?

[axur-delmeria]

So disconnect the LCD cables and plug in an external monitor to the VGA port on the side and see if anything comes up?

Yes. With the LCD disconnected, the laptop should default to another video output, usually the VGA port.

What about the lid switch? Where is the lid switch even at? In the socket where the screen hinge mates with the chassis?

I've yet to own a T420, so I'm not sure myself. The lid switch is actually a Hall effect sensor, sensitive to magnets.

In my X220 the sensor near the webcam, and the corresponding magnet is somewhere below the touchpad.

It's possible that the T420 has a similar setup. The T420 HMM's FRU listing mentions a "Magnet - suspend switch" as part of "Keyboard bezel miscellaneous parts" FRU 04W1603.

[gfuller]

So disconnect the LCD cables and plug in an external monitor to the VGA port on the side and see if anything comes up?

Yes. With the LCD disconnected, the laptop should default to another video output, usually the VGA port.

What about the lid switch? Where is the lid switch even at? In the socket where the screen hinge mates with the chassis?

I've yet to own a T420, so I'm not sure myself. The lid switch is actually a Hall effect sensor, sensitive to magnets.

In my X220 the sensor near the webcam, and the corresponding magnet is somewhere below the touchpad.

It's possible that the T420 has a similar setup. The T420 HMM's FRU listing mentions a "Magnet - suspend switch" as part of "Keyboard bezel miscellaneous parts" FRU 04W1603.

Okay. Thanks.

That's an interesting setup. I never would've guessed that they would use magnets and a Hall Effect sensor, but I thought they would've hid a microswitch somewhere in the hinge mechanism. My T42 has a switch that is clearly visible, so I guess that's where I got that thought.

[axur-delmeria]

That's an interesting setup. I never would've guessed that they would use magnets and a Hall Effect sensor, but I thought they would've hid a microswitch somewhere in the hinge mechanism. My T42 has a switch that is clearly visible, so I guess that's where I got that thought.

I suppose the idea is that Hall Effect sensors have no moving parts, so no wear and tear compared to microswitches.

[gfuller]

That's an interesting setup. I never would've guessed that they would use magnets and a Hall Effect sensor, but I thought they would've hid a microswitch somewhere in the hinge mechanism. My T42 has a switch that is clearly visible, so I guess that's where I got that thought.

I suppose the idea is that Hall Effect sensors have no moving parts, so no wear and tear compared to microswitches.

Makes sense.

[gfuller]

I've been busy lately - not to mention trying to think about what to do.

1. So it's pretty clear that I should just go ahead and replace the system board. First problem is - where can I purchase a system board? Are most versions readily available on eBay? I'd like to keep mine as it was (meaning same CPU and GPU, meaning it will need to have the GPU socket), so will I just need to find another system board that bears the same FRU number?
2. Will anything else need to be purchased alongside a new system board for proper installation?

In the meantime I'm thinking about maxing out the memory in my T42 (my current workhorse that has been picking up the slack) to the full 2GB DDR memory.

[Thinkpad4by3]

Yes and no.

1: If you have a bog standard i5 or i7 dual core w/o graphics, 30$ will get you a new board shipped from eBay. Match the FRU!!!

2: Nope, its "plug and play"!

[gfuller]

Yes and no.

1: If you have a bog standard i5 or i7 dual core w/o graphics, 30$ will get you a new board shipped from eBay. Match the FRU!!!

Mine has dedicated graphics, and I'd like to keep the Nvidia GPU if possible. I'm guessing that a system board with a matching FRU should have a GPU socket and should be pretty much identical?

[turomini]

same FRU will be identical parts. Just watch the buyer, and check the parts when you first receive them.
The T420s has a soldered CPU and a optional dedicated GPU, in the hardware maintenance manual, there is 26 FRU numbers for each combination of graphics and cpu. Just get the same one and you will have an identical part. Look through the HMM and you might find an upgrade, but I don't know the setup of a T420, only T420s. There might only be a board for dedicated graphics and integrated since I know the CPU has a socket and I guess the GPU will also.

These are the only FRU that will have the dedicated graphics.
04W2049 - System board assembly, discrete graphics, AMT, TPM
04W2050 - System board assembly, discrete graphics, AMT, non-TPM
04W2051 - System board assembly, discrete graphics, non-AMT, TPM
04W2052 - System board assembly, discrete graphics, non-AMT, non-TPM

AMT - Intel Active Management Technology
TPM - Trusted Platform Module

I just checked ebay, only 04W2049 has any matching listings, I think starting around $50.
I don't think there is any difference for you between those 4 boards, so you are fine to switch between those 4 FRU. AMT and TPM isnt something most general consumers will utilize, and the boards should have the same connections and dimensions. Of course, double check everything you can before buying any. Not all sells are good about properly identifying their own products also.