Dell M4700 REBUILD #1 - My Laptop Is **DEAD** But Not For Long!

DELL PRECISION M4700

My **CRAZY** Dell Is DEAD - But Not For Long!

I bought CRAZY, a second-hand DELL PRECISION M4700, for CAD350 (USD267.51) in the early days of June 2018 out of the back of a car in the parking lot of an Ottawa Real Canadian Super Store...no kidding! 

I was responding to an ad with the following headline:

Dell Precision M4700 Mobile Workstation Laptop w/ Firepro m4000

I found it on Kijiji, Canada's version of Craigslist.  

Here's the general specifications of the machine:

• Dell Precision M4700
• CORE i7 CPU (i7-3520@2.9Ghz)
• Firepro m4000
• 8Mb RAM
• 128Gb SSD

So, I got in touch with the seller and planned a buy:

The person selling the computer, "Bob Walter", was obviously using an assumed identity, because he looked about as much like a "Bob Walter" as I look like a "Xi Jin Ping".

Anyway, despite its somewhat turbid provenance, the DELL PRECISION M4700 seemed to work just fine when I checked it out.  The battery was OK.  It seemed to be in fine cosmetic shape.  It came with a 128Gb SSD.  At the time of the purchase, the machine booted correctly and brought up a Windows desktop quickly and smoothly.  There was no obvious damage.  So, I was pretty pleased with the buy.

But, very shortly thereafter, even before the summer was over, it started to develop a very strange video problem that looked like this:

Taking a look at the machine, I noticed that the machine appeared to have a heat problem, because the right side of the keyboard was becoming very hot to the touch.  Too hot.

There are two fans on the DELL Precision M4700.  Looking at the screen, the one on the left cools the CPU, the one on the right cools the GPU.  Servicing the fans is pretty easy, you just flip the machine over, release the battery, unscrew a couple of baseplate screws, remove the baseplate and there you are.  The fans are in plain view (but reversed, the GPU fan is now on the left instead of being on the right, because the machine is upside down).

In the end, it turned out that the machine had a serious GPU cooling issue.  The GPU airflow was being blocked by what looked like a large clump of fluff and cat hair caught in (and hidden by) the exit port heat dispersal fins.  So, I removed the blockage and blew out the machine with compressed air.   The machine booted smoothly as always, and there was no more flickering video.  I thought I had resolved the issue...but I was wrong.

As it turns out, the primary user of the machine was still experiencing flickering video issues, just much more rarely.  When interviewed about this after the system failure, they said "When the video turned off completely, I would just wait a little while and it would come back on - it happened so rarely, it just didn't bother me and I didn't think about it any more".  

Hmmmm - that's not really an acceptable MAN THE MAKER situation...

One day, the machine simply froze.  Not thinking much of the situation, the primary user performed a hard restart and....nothing.  The machine powered up and then then just sat there doing absolutely nothing.  No beeps!  No nothing!  Just a power indicator above the keyboard and nothing else.  

The other thing that happened when this machine crashed is it somehow managed to scramble the contents of its SSD to the point where the disk became unrecognizable by any other computer.  I had to buy an external USB enclosure to get it recognized and the data off the disk and onto a replacement computer.

So, with the machine much deeper in trouble, back into troubleshooting mode I went.

I did the following to try to isolate the source of the problem:

1) I removed all of the memory, to checlk if there was a memory error and to elicit some beeps from the computer.  No beeps.

2) I removed the CMOS battery, thinking that there might be some weird CMOS setting with respect to the HDD preventing the machine from booting, but got nothing.

Because I was a  bit short on time, I called a local laptop repair shop and asked them to take a look at the machine for me.  

I don't normally do this - but I was about to travel overseas and it was imperative to get this machine back online as soon as possible.  

I told the technician everything I could about the machine (including the story of the blocked GPU fan) and said that I suspected that it was the graphics card that was faulty.  The technician called me later on the same day and said that a replacement of the graphics card would cost about USD75.00, labor included.  I told him to go ahead and get one, put it in, and tell me whether or not that fixed the problem.

I returned from my travels about a week later, only to be told by the technician at the laptop repair shop that he had been unable to repair the machine.  Furthermore, he wasn't sure what was wrong with it.  He told me that after he had swapped in a new graphics card, the machine still refused to boot.  

At that point, I asked him to box the machine up so I could come and get it.  The technician was kind enough to box the machine up quite nicely, and I went and got it without any issues - only to realize that he had forgotten to give me the bottom plate of the laptop, which bears the DELL SERVICE CODE I needed to get the "as built" specifications of the machine.

Once again short on time, I put it away - but promised myself that I'd take another look at it when I had a little more free time.  Well, that time is now!

When I got the machine back I noticed something about it right away.  The thermal compound that had been applied to help conduct heat from the GPU to its heat sink was now the consistency of hardened drywall plaster!

In fact, the area where the GPU came into direct contact with the heat sink had baked the interfacing thermal grease A DARK BROWN.

Clearly, no replacement card had ever been installed.

The technician had told me a fib.  Who knows why...

This left me in a bit of a pickle, because I didn't know where the fault truly lay:

Potential Fault Origins:

A)  Was it the GPU board? 

- Was it fried permanently from having not been cooled correctly for years?
- Was it just overheating the instant the  machine was powered up?

B)   Was it the CPU?

- If the GPU thermal paste was bad, surely the CPU paste was in the same state?
- Could the CPU be fried?

C)  Was it the motherboard?

- After all, the machine was 5 years old and suffering from thermal issues

Using Occam's Razor as my guide, I figured that the first component to mess with should be the GPU card, because the machine had a history of video problems, and those problems diminished (but did not disappear) when the cooling subsystem had been straightened out.

So, I figured that the simplest thing to do was to:

Re-assemble the computer 

- With the  same Graphics Card
- With fresh thermal paste
- With clear airflow

How To Remove Thermal Paste (Use Rubbing Alcohol!)

Removing thermal paste is easy if you use rubbing alcohol and a bunch of Q-tips.  Simply apply the rubbing alcohol generously to the Q-Tip (I dip the Q-Tip directly into the bottle) and then rub the hardened thermal paste in a circular motion until it starts to dissolve.  

After a few minutes of this, an AMD chip face emerged:

Here's some specifications:

Part #:            216-0834044
Device Type:    Video Card
Manufacturer:    AMD
Product Line:    FirePro M Series
Model:             M4000
Description:    FirePro M4000 Chelsea XT GL 1GB Laptop DDR5 Graphics Card
API Supported:    DirectX 11, OpenCL 1.2
Enclosure Type:    Internal
Graphic Processor: AMD FirePro M 4000
Memory Size:       1 GB
Memory Technology: GDDR5 SDRAM
Memory Interface:  128-bit
Core Clock:        600 MHz
Memory Clock:      4500 MHz
Resolution:        2560 x 1600

Good to know.

After a few minutes of gentle rubbing (and about 10 Q-Tips), everything was clean again:

And then I cleaned the matching face on the Dell M4700 heat sink too:

This style of heatsink is called a Heat Pipe, because it is designed to use fancy physics to transfer heat being generated at Point A to a cooling strategy located at Point B.  

Heat Pipes are designed to conduct heat from one place to another using a highly heat-conductive material (in this case, copper) that transports the heat to another place where  it can be dispersed - in this case, via airflow located some some inches away, instead of focusing the airflow directly on the source of the heat itself.  Why?  Mostly because laptops need to be thin, and a vertical cooling strategy (like in a desktop computer) would be too thick.  Laptops need to cool horizontally, not vertically.  That's what a Heat Pipe makes possible.

Anyways, the sorry state of the thermal compound on the GPU make me suspect that the exact same thing had happened to the CPU, so a complete disassembly was probably in the cards once this machine had been brought back to life.

My first task was to get my hands on some fresh thermal compound!


I bought some thermal compound and re-applied, but that didn't work.

I bought a blowtorch and tried to reflow the BGA under the GPU, but that didn't work


So, I went ahead and bought another video card, because the one I found cost less than USD10.00:

Put in commentary about pressing "D" and the power switch to fire off the LCD test to prove that the backlight is working.

Put in commentary about pressing "<Fn>" and the power switch to fire off the DIAGNOSTICS test to  

Here's a video on how to disassamble the DELL Precision M4700.

REFERENCES:

https://www.youtube.com/watch?v=xvvQxPMATko