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Updated 02DEC2008
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Box and Unit.
Under the scope.
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AeroCool EasyWatch, Testing Methods & Mods.
How do I use the temperature meters?

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Idea#014 Page 5

Measurement locations and methods.

requirements;
1: A firm grasp of electronics, and thermodynamics.
2: A good thermometer with an ultra-thin type sensor.
3: Some weather stripping and tape with non conductive adhesive on both.

Regular heat sinks get cooled by air flow, You will never get an accurate reading off of the cooling fins. You need to get to the under side of the heat sink where there is little to no air flow.

meant to be there
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If your lucky, some heat sinks have a spot the sensor will just slide into, as if it was meant to be there.

under heatsink
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there and not so there
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Some heat sinks are larger then the chip there cooling, so the thin sensor can be slid between the PCB and the underside of the heat sink, up against the chip. However this location has a pitfall, in the side picture you will notice the sensor is flexing away from the heat sink. Unless you can see where the sensor is going under the heat sink, another method might be better.

under TSOP or dip
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In some rare cases, and in the old days, the sensor could be slid between the DIP, and the PCB. A location with minimal air flow, and close proximity to the hot glass inside the DIP.

back of PCB
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back of PCB coverd
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For the chips that lack a place to mount the sensor under the heat sink or under the chip, without crushing the sensor. The other side of the PCB is the next best spot. Chances are the largest trace dead center on the chip is either the power trace or the ground trace. These traces are usually connected to multiple pins on the chip allowing the best thermal connection to the chip it's self. Placing the little nub at the end of the sensor strip dead center of the chip on that thick trace and covering that location with a small amount of weather stripping to prevent moving air from skewing the measurement will give a close enough reading for most modest case mods.

Just remember, if the sensor dose not slide easily under the chip, or heat sink, DON'T force it.

And last but not least, I will not be held responsible for how well or disastrous your testing results are.


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Home > IdeasEasyWatch, Intro.
Box and Unit.
Under the scope.
Conclusion.
Testing Methods & Mods.

Fan speed without the unit powering the fan.

Don't even bother reading on if you haven't at least gone to school for basic electronics, and passed the course.
That or managed to get your Armature Radio License prior to 1991, and still have an active call sign entry in the FCC Armature Radio License database. At witch case, you probably already know this.

If your about to try to modify a four wire fan, STOP, skip down to and reed the "Last Note".

Just remember that every thing has to be assembled some how. Most plugs consist of a plastic non conductive housing, and little metal things, that snap/clip into the housing, after there either crimped and/or soldered to the wires. Most plugs can easily be disassembled with the right pick or tiny flat head jewelers screwdriver, and allot of finesse.

Usually there will be a little tiny springy tab holding the metal part in the housing, that will break if you look at it wrong. This little tab needs to be lifted off the metal part, or if part of the metal part pushed down to allow the metal part to slide out of the housing.

disassembly
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disassembly
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I suggest practicing with some dead fans first. When you get it down to the point that the wires come out of the plug, and easily snap/clip back in without falling back out, it's time to snag one of the plug housings off of a dead fan to connect the tachometer wire to.

plugs-n-wires
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presto
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Now that a dozen fan plugs have been destroyed figuring out where to press and/or pool and how they come apart. Pulling the one wire that is not black, or red, usually it is yellow on the triple wire fans, and placing it in the same spot on a separate identical connector housing, should be as some say "easy".

books
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The sad thing is, most motherboard manuals include the pin out of the three pin fan connector, and as follows.
pin 1 is ground (black),
pin 2 power (red),
pin 3 RPM sense (yellow).

Now the power can come from the plug with two wires in it (presumably black and red), go ahead and plug that one back into where it use to be plugged in. Now that other plug with the single wire (presumably a yellow wire), can be connected to your RPM meter (RPM +sig) input, any ground in the computer will work for the RPM common/return/-sig. The EasyWatch mini thing, has it's own ground from the power plug, so no more work is needed for the EasyWatch to only monitor fan speed. Just plug it in.


Last Note.
I don't think this fan RPM meter mod will work with most, if any, four pin fans. The newer CPU fans include a RPM control wire. The fan control circuit on the motherboard probably needs to know how fast the fan is spinning to operate properly, as part of it's RPM feed back circuit. Splicing the RPM sense wire off to a second connector will probably put to much load on the RPM circuit in the fan to operate correctly, if not destroying the fan, meter, and the motherboard. Could some type of buffer amp thing allow both to read the signal safely, start your home work on all four items involved. I don't know the sense circuit impedance, terminating method (to ground/power/else ware), signal levels, or current draw of each unit reading the signal. It is feasible to devise something to allow both to read the fan RPM, without putting unnecessary strain on the circuit in the fan. Thats another "op-amp voltage-follower" electronics project for another day, assuming that an op-amp can handle the current draw of the motherboard circuit and the meter combined.

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