How to: Replacing Cooling Fans and Thermal Compound on a Video Card

 

Introduction

I have several older video cards that have been dutifully mining for the past 3, and in some cases 4, years now and the wear and tear is starting to show. Out of approximately 30 Gigabyte cards, I have had to take advantage of the three year warranty and RMA about 6 of them, or about around 20%.  Four of these were early on in their life-cycle, as Bitcoin mining (when you could still make a small profit off of GPU mining) was hot and hard on them.

Then later came scrypt mining, and with many tweaks to both under-volt and under-clock the cards, they enjoyed a more pleasant “mid-life” than they did during their tenacious youth. In that more leisurely 2 year time span, I lost 2 more cards, I suspect some still felling the strain and abuse from their early years.

Now many of these cards are entering their senior years and living out their remaining time mining away on Dagger-Hashimoto algorithms, such as Ethereum. Fortunately, while memory hard, this algorithm can also be ran in a more relaxed state, helping keeping voltages and temperatures in check. While complete card failures and burn-outs are less frequent, the moving parts, namely cooling fans, still have a hard time. It is hard to keep dust and dirt from gradually coating and eventually blocking everything, and I have started to see more fan failures than before.

 

Gigabyte HD7970 with 2 bad cooling fans
Gigabyte HD7970 with 2 bad cooling fans

 

With the classic Gigabyte HD7970 Windforce (shown above) with its three cooling fans, a single fan failure is acceptable as the other two still provide plenty of airflow. However, once two fans go it is time to take action. This article is going to cover this “maintenance” of aging cards and go over the basics of replacing a failed (or failing) fan. While not as easy as one would like, it is also not necessarily a very difficult procedure, you just need to find a quiet, well lit, area to work and not be in a big rush.

Much of this procedure can also be used for similar maintenance, such as taking the card apart to really be able to clean out the built up dust and dirt, that you just cannot get to with a fully assembled card. So even if your fans are still working fine, but you are itching to get at some of that gunk, follow along as this will also pertain to you.

Arctic Silver 5 009Since we will have the heat-sink off in all these procedures anyway, a third option is to “upgrade” the thermal compound to a better quality, in this case I am using Arctic Silver.

Some enthusiast gamer’s, or even miners, even those with new or perfectly functioning cards will often remove the heat-sink to replace the thermal compound with Arctic Silver or similar. Many swear by this and claims are of up to a 10° Celsius drop in GPU core temperatures simply by carefully applying a quality thermal compound. While this article is mainly concerned with replacing the fans, if I can get better temperature control in the meantime, great I am all for it.

As you can see in the image of the graphic card above, this GPU is quite dirty, with the heat-sink and fans area covered in dust. I periodically shut my rigs down to vacuum and blow them out, but since this one has two dead fans I will clean it up thoroughly once it is disassembled.

Disassembly

Lets get started.

First off the disclaimer. While if done carefully and correctly this procedure is fairly simple and can be done with minimal tools or experience. However, if you attempt to follow along and work on your own video card, you do so at your own risk, as I have no control over the many variables involved. As with anything, there is always a risk you could make things worse and void your warranty, and/or rendering your video card useless in the process.

One last note, the greatest danger may come in the form of a static discharge when working around the sensitive components. I use a grounded static work mat, but most people will not have this so at a minimum try to discharge any static electricity you may have on you when working on your card. Simply touching a grounded metallic appliance, like your Desktop PC may be enough. Also avoid this type of work in a dry environment, such as in a non-humidified house in the winter. If you got shocked by static at all today, this is not a good time to be doing work like this.

To do this procedure, the required tools are minimal, but you should have at least a needle nosed pliers and a small precision screwdriver set as the screws are very small. These both can be picked up for a couple of dollars at most any hardware store. A can of cleaning air is also recommend to help blow out dist and debris through-out the process. Canned air is recommend as it is clean and dry, so using it will not contaminate any parts. Also, you will need some type of thermal compound as we will need to remove the heat-sink to properly get at the fans. There are many good brands out there and this is readily available at online stores like NewEgg or Tiger Direct. Other items are 99% isopropyl alcohol and a new clean lint free cloth or cleaning pads.

HD7970 Fan Repair 001

The metal end-bracket cannot be removed completely right away, as there is a small screw attaching the bracket to the PCB (Printer Circuit Board) that is inaccessible until the fan shroud is off and out of the way. However, I have found it useful to remove the single screw and two “nut screws” (shown on the left) right away to loosen things up a bit and to make it easier to remove the shroud later. A small Phillips screwdriver and a small pliers, needle nose works good, quickly removes these fasteners. The bracket could remain in place as well, as this step is optional, depending upon how much play there is between the shroud and bracket.

 

HD7970 Fan Repair 004

Flipping the card over you will need to remove the 4 screws, as shown circled in the image on the right, that hold the heat-sink assembly (including fan shroud) to the PCB. These are small, but snug,  so if you use a precision screwdriver you may need to grip it with your needle nose for the first half-turn in order to break the tension and make it easier to loosen the rest of the way by hand.

If your work surface has one of those rubber grip type mats this works easier, or you may need to enlist the help of someone to lend a hand to hold the GPU when you do this step. You could use a small vise, but due to the danger of damaging a component, I would recommend against this. Depending on your GPU, there may be other screws you will need to remove, but most of the cards I have worked on use only these four. If something seems too tight, check it out there may still be a hidden fastener somewhere.

 

With the four mounting screws removed, you can gently separate the heat-sink and fan shroud combination from the PCB. Try to do this by hand only if possible, and gently apply pressure trying to separate the two halves as you work your way around the board. Most of the pressure is going to come from where the heat sink attaches to the GPU in the center, but heating over time can cause certain thermal compounds to act as sort of an adhesive.

If you do need to pry, which I recommend against, try to find something blunt and soft like an old paint stir stick, rather than something hard and metallic like a screwdriver. Also, be sure to pay attention to where you apply pressure if you do try to pry it apart, as you want to avoid damaging any on-board components. I have always managed to just separate the two halves by hand, so keep giving this method a shot before getting too impatient. Applying even pressure along with a slight back and forth wiggling usually does the trick.

 

HD7970 Fan Repair 006

Once you manage to separate the two halves, be careful as the fan shroud has a small electrical connector for the fans that will still be attached to the PCB. You can remove this connector with a gentle lifting action. You may need one of your smaller flat-blade precision screwdrivers to assist if you encounter too much resistance. If you examine this connector closely, you will notice two tabs on the white connector mounted to the PCB that you can very gently try to pry out a bit to ease removal of the plug end.

Once the electrical connection is unplugged and the two halves are now independent of one another, you can set the PCB board aside for now. Note that you could also remove the metal end bracket at this point if you wanted to,a s you should be able to access the small screw attaching it to the PCB. I usually leave it on,but if you ware worried about braking it off, you could remove it completely until you are ready for reassembly.

 

HD7970 Fan Repair 005

Turning our attention to the heat-sink/fan shroud half, we can continue the disassembly procedure. You should be able to locate the four fan shroud attachment screws, two on each end, that hold the shroud to the heat-sink. You can see two of the screws on one end in the picture at the right. Remove all four of these screws and gently lift the fan shroud off the heat-sink assembly.

 

HD7970 Fan Repair 013

 

As you can see in the above image, now that the major components are disassembled, you can easily work on the fan replacement. It is also a good time to vacuum out all the dust and dirt. You may need to spray some canned air through the fins (do this outside) to get at the real deep seated dust. Just be careful as the heat-sink fins can be easily bent and damaged, this reducing the airflow we are working so hard to improve.

A small cup helps keep all the small parts organized.
A small cup helps keep all the small parts organized.

Now that the fan shroud is detached and on its own, you can also give that a quick once over with the vacuum and canned air if desired to make it easier (and cleaner) to work on. If blowing air near the fans, try to hold the blades still to keep them from spinning, as if they rotate too fast this can result in an “over-spun bearing” which basically will wreck the fan. If all the fans are already dead this doesn’t matter as much, but in my case one of the fans was still operational and I wanted to keep it that way.

Looking at the image below, you can see the fans are mounted with three small Phillips head screws each. As you can see, the screws are partially hidden behind the fan blades. You will need to access these screws through the fan blades themselves, and will need to rotate the blades a bit as you work to open up a “pathway” with which to remove the screws. A slightly magnetized screwdriver tip is useful for this, as you can then lift the screw out once it is free. If you don’t already have one, a few swipes of the screwdriver tip across a strong magnet will usually suffice.

HD7970 Fan Repair 015

 

Go ahead and remove the screws for any fan(s) that needs to be replaced. In my case, one fan was working well, but I removed it anyway to be able to more easily clean the shroud and blades of the the good fan. You may want to mark which fan is which somehow (tape, marker, etc.) if this situation applies to you, so you don’t mix them up later.

HD7970 Fan Repair 016To the left, we can see the wiring harness on the back side of the shroud. All of the fans that are going to be removed will need to be disconnected from the harness. This is the same type of connector that was used to attach the harness to the PCB, so again you may need the help of a small flat-blade precision screwdriver to gently pry it apart. In my case, the good fan was the last in line, so I just left it connected to the harness for easy identification later on and I just removed the two bad fans that will need to be replaced.

HD7970 Fan Repair 021

With all of the fans removed, I gave the shroud a quick rise with water a bit of dish soap to remove all the dust and grit that had build up over time. I also very gently used a dampened piece of paper towel dipped in the dish soap solution to wipe each fan blade down. Do not rise the fan as this will wreck it, but a slightly damp paper towel applied just on the blades can help remove any stubborn dirt that vacuuming/blowing did not dislodge.

Now with the fans out of the shroud, we can take a closer look at one of them and see what information we will need to acquire for a replacement fan. You may, or may not, have good luck with getting an exact replacement fan, especially if you are looking to source it for as low of a cost as possible, but we can still determine the specifications of the original so we know what to search for when looking for a replacement.

We will look at finding a replacement fan on the next page.

Be the first to comment

Leave a Reply

Your email address will not be published.


*