The Fast, Cheap, and Easy Fix

The "Fast, Cheap, and Easy Fix" is my preferred method of enhancing air circulation in a computer case. Basically, it is the opening up of one or two slots at the lowest positions. It works because the power supply fan is often restricted (the grill inlet is too small)... Like trying to drink a thick milk-shake through a straw. The bigger the straw diameter, the less work it is to drink.  Objective: Help the air flow to go in at the bottom and come out at the power supply without restrictions.

Widening the air inlet to the case is the best quick fix for owners of generic mini, mid, and tower cases. I have found that most of these cases made in the last few years have restricted inlets. In fact, one of my cases had virtually no inlet because the plastic flashing over the front grille was too thick to easily remove. (What do you want for $35?). I first noticed that the fan did not blow as much air when the case cover was on as compared to being off. 

 The first point here is to make another opening in the case at the lowest possible location. The second point is the opening must be equal to or larger than the area of the power supply fan. To do that, we will remove 1 or 2 of the slot cover plates in the back of the computer. The 2 arrows in the photo point to the newly created openings. 
 

Please make sure you have read the first page before deciding to do this. Allow about 45 minutes to complete. Here are some definitions- 

• Card- Any adapter card such as a sound card or internal modem
• Slot- As used here, a slot is the opening or space where a card goes. It also means the electrical connector a card plugs into.
• Cover plate- The "L" shaped metal part meant to block off a cardless slot. Cover plates are often thrown away when new cards are added to a computer.

Step 1. Power Off, and unplug the power cord. 

Step 2. Look at the back of your case. Sometimes cables are too short to get good working room when removing the case cover. If so, make a note of any cables coming out of it so you can replace them properly, then disoconnect them. 

Step 3. Open the case cover. (True computer doods will have 2 or less screws holding the case closed). 

Step 4. Make a decision on how many cover plates to remove. Look at the front of your plastic computer case from the inside out. If you see A LOT of large air holes in a grill pattern, you only need to remove 1. If you have thin slots or small air holes, remove 2. 

Step 5. If cards are in the bottom 1 or 2 slots, you will need to move them up to other open slots. Most likely these are ISA cards and hopefully you have enough ISA slots. Unscrew the cover plates (if the slot has no card) or cards (if the slots are not empty) and replace the screws. Move the cards up as needed to free up the 1 or 2 slots you selected in Step 4. The open slot(s) MUST be at the bottom! 

Step 6. Seal up any large openings in the back of the case, especially any slots above the lowest 2. You should use the cover plates you just removed. If there are any DIN knock-outs open (Serial or Parallel connector openings) closing them with a piece of duct tape (see figure) would be a nice touch, but not absolutely required. 
 

Step 7. Replace the case cover, cables, and boot up. Test any cards you may have moved and you are done. Note: for the FCE fix to have any effect what so ever the case cover must be ON with at least 1 screw.

Congratulations. Now you have a more robust computer system. Put your palm about ½ inch from the fan. After the computer has been warmed up you should feel more air blowing out of the fan compared to before. The air should not be as warm as before. The relationship is; higher air flow has a lower temp. Less airflow has a higher temp, for a given thermal load.   REMEMBER- This modification is reversible. You can always restore your computer to its original configuration.

And now a word about dust. In the long run dust build-up on electrical components can be harmful. But I have seen some computers several years old with a thick build-up running without any problems. The Fast, Cheap, and Easy Fix should not increase your dust build-up any more than would be seen by a case properly vented in the first place. But, premium quality cases will have an air filter on the inlet to the case. 

Using the Fast, Cheap, and Easy (FCE) fix, I achieved a 26 degree Fahrenheit reduction in case temperature! That means the air and components inside of the case were cooler, increasing reliability and life span. 

Here are photos of that system. It’s a Cyrix P150+ overclocked to a P166+ on a Tyan Tomcat 1 motherboard, 32 megs, 2 Western Digital hard drives (2.8Gig total), a Network Interface Card, Sound, and CD-Rom. The power supply is 230 Watts. 
 

BEFORE: 132 Degrees fan exhaust temperature (Click to enlarge)	AFTER FCE: 106 Degrees fan exhaust temperature (Click to enlarge)

The original temperature the system operated at was 132 Degrees. Opening 2 slots dropped the temperature down to 106, a difference of 26 Degrees. In the photo you can see an LCD thermometer which includes a relative humidity readout of 15% (humidity makes no difference to computers) and an ambient temperature of 83 Degrees*. The middle meter also shows the ambient temperature of 83 Degrees. It’s sensor is located at the end of the yellow wire suspended in air about 8" above the floor behind the meter. The meter on the right shows a temperature of 106, as measured ¼" away from the fan at the upper back of the case. The yellow wire with its sensor can be seen heading over the top of the case to the rear. 

* Usually summer ambient room temperatures are 77-80 Degrees. This data was taken when the room temperature was 82-83 Degrees. There were 4 computers on in the room and I live in the desert where air conditioning bills are dependent upon how cool the house is kept. Keep in mind that you can subtract small changes from both temperatures (ambient and case) to compare to these results. 

230Watt and 250 Watt power supplies contribute a 5 degree (+/- 1) temperature rise. Therefore, the actual internal case temperature was 132 - 5 = 127 Degrees. It is far more convienent to monitor and treat case temperature as if it were the internal temperature, and that is what I recommend doing. Here is my worst case and improved temperature data in table form; 
 

 Note: In order to ensure the accuracy of this test, it was performed in this order. The 2 slot plates were removed. The case was assembled and power on for an hour. The 106 Degree temperature was recorded. Next, while the computer is still on, a piece of duct tape was placed over the slots to simulate installed slot plates. The piece of the tape can be seen in the photo at the back of the case. The temperature began to rise rapidly, achieving 124 Degrees in only 2 minutes, 130 in 15 minutes, and a steady state temperature of 132 Degrees in 30 minutes. Removal of the tape reduced the temp to 109 in 15 minutes and 106 in 45 minutes.

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 © 1997 Darrell Clark,  
dclark@desernet.com