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nVidia GeForce 7800GT Fan Controller Fix



For those who have owned a 7800GT graphics card from nVidia, it may have quickly become noticeable that they are not quiet cards. But that isn't always the case. nVidia released those two cards with a faulty surface-mount transistor. This transistor is labeled Q524 on the 7800GT board. The problem that this transistor causes is very noticeable. Over half of the time that this card initializes, the fan-speed controller never starts. This leaves the fan at full speed until it is reset, which sounds like a vacuum cleaner. It can take up to 20 resets of the host machine before this card will initialize the fan controller as intended. But do not worry, there is a fix.

For this repair demonstration, I will be using my OEM 7800GT over-clocked card by BFG Tech. I do not have a 7900GT, however, if the problem is caused by the same fault, the transistor is labeled with a different number than that on the 7800GT. Any other 7800GT that shows the fan speed symptoms described above will require the same fix. You must have previous knowledge of soldering and proper care/handling of CMOS components before attempting this repair. CMOS components are static sensitive. Do not touch any metal contact unless you must. It is recommended that you wear a grounding strap. This repair will void most replace/refund warranties. The tools you will need are listed below.

Start by removing your card from your PCIe slot and placing it on a wood or grounded metal table. Rotate the card to the back position as shown. In this picture you will see a red circle enclosing the area that we will be focusing on. You may find it appropriate to acquire a magnifying glass if you have vision trouble.
The picture on the left shows the closeup of the transistor and bridge that we will be working with. You may choose to circle this area with a marker so that you do not lose it during the procedure.

Allow your soldering iron to warm up and tin it appropriately. Enclose transistor Q524 with the tweezers as shown below. Heat each lead as ordered 1-3, and softly rotate upward in the opposite direction. Do not squeeze! Apply gentle pressure to coax the component out of position. Do not force the component out of position until the pad is properly heated. Avoid breaking solder pads off of the board in case you want to replace the component. The board should look like the second half of the picture below after removal of transistor Q524. Make sure you did not create any solder lines making unwanted connections.
Direct your attention to the two dots to the right of the transistor socket. Carefully create a bridge of solder between the two points. It should look similar to the image below. Alternatives such as conducting fluids are said to work. I have not confirmed such alternatives.
That's it! Keep the transistor in case you want to put it back. It is very small, so I recommend taping it to the board (away from any contact points). Your fan speed should initialize correctly every time you start your PC. This will allow for control from software such as RivaTuner as well.
Windows must be started, and the driver must initialize before you will hear the fan speed drop. This is normal. Please contact me if you have any problems with this repair. To soothe any concern about attempting this, I can assure you that this repair has been replicated globally. I have done it to both of my 7800GT cards. If you are uncomfortable doing this yourself, you should hire a certified technician and show her/him this article.
Written By: Erik Greif
Published: 05/27/2013 11:30PST
Modified: N/A
Article Title: nVidia GeForce 7800GT Fan Controller Fix
Article URL: http://bitfracture.com/?page=techarticles/nvidia_7800_gt_fan!techarticles
Website Title: Bit Fracture Online
Website URL: http://www.bitfracture.com
Media Type: Blog Post/Personal Article
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