Cooling Fans

This page is the by-product of my spec'ing out the FBK-09A12L fan in my 8573-P75.

> The fan stops from time to time, causing the system to get dangerously hot.

Dave Burton replied:
   You asked the right guy. :-) I've become somewhat of an expert on this topic. :-|

That is a very common problem with clone computers, though they usually wait more than the warranty period before dying. I first tried replacing the bad fans in my computers with Radio Shack's equivalent. But they were at least as unreliable as the originals, probably worse.

So, I bought several fancier (ball-bearing) fans from Digi-Key. They carry two brands: Rotron/Comair and Panasonic. I bought a few of each. I was surprised and disappointed to conclude that I like the Panasonics slightly better than the Rotrons, even though the Rotrons are more expensive. Rotron gives a MTBF of 60,000 hours for these, but Panasonic gives a *guaranteed* lifespan of 40,000 hours, which I think is better, too. (Lifespan ratings are for operation at a temperature of 25 Celsius.)

40,000 hours is about 4.5 years of continuous operation. Not great, but a lot better than the miserable made-in-China originals in these clone computers.

(One good thing about IBM computers: they *do* put decent fans in them, unlike most clone vendors!)

Both Rotron/Comair and Panasonic fans come in both of the two popular sizes for clone computers: 92x25 mm, and 80x25 mm (note: you almost always need 12v DC fans in PC clone computers, so don't get the 24V models).

In the Panasonic ball-bearing fans, you have these choices, all at $18-19 each from Digikey:

SizePowerAir flowAir pressureNoiseModel
80x25 mm0.66 W22.6 CFM1.8 mmH2O23 dB-AFBK-08A12L
80x25 mm0.98 W29.0 CFM3.1 mmH2O29 dB-AFBK-08A12M
80x25 mm1.56 W37.1 CFM4.5 mmH2O35 dB-AFBK-08A12H
92x25 mm0.96 W35.3 CFM2.5 mmH2O27 dB-AFBK-09A12L
92x25 mm1.13 W41.0 CFM3.3 mmH2O31 dB-AFBK-09A12M
92x25 mm1.64 W48.4 CFM4.4 mmH2O35 dB-AFBK-09A12H

I would suggest the "M" versions, normally, or for minimum noise (but minimum cooling) the "L" version. The "L" version is probably closer to the original that you're replacing -- these clone computers often have very anemic fans.

(Panasonic also has non-ball-bearing fans, for about $5 less... but why would anyone want one? The specs and model numbers are similar, but the model numbers start out "FBA-" instead of "FBK-", and there's an extra "1A" on the end. E.g., FBA-08A12L1A for the 80mm, 12V, Low-capacity version.)

The Rotrons you want are the "Flight II 90 series" and "Flight II 80 series" (for 92mm and 80mm fans, respectively). They sell for about $24-25 each from Digikey. In the 80mm fan, you can get either the 1.8W version (33 CFM) or the 1.1W (quieter, but only 26 CFM). In the 92mm fan, you can get either the 3.7W (45 CFM) or the 2.4W (38 CFM).

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