Installing a peltier/TEC on a Dothan: A step-by-step guide

Using peltiers and TEC to cool CPUs is not a viable option with the high powered new processors. The power hungry processors, such as the Prescott make most peltiers inadequate. However, cooling the Pentium-M Dothan processor is the perfect application for a peltier. The Dothan only puts out a max of 27w of heat stock, and overclocked, it probably outputs below 80w of heat. If you would like additional information on the Dothan processor and why it is one of the best cpu's available today, please see the following threads.

http://www.ocforums.com/showthread.php?t=385836&page=1&pp=30
http://www.ocforums.com/showthread.php?t=393963

This guide will show you step-by-step how I setup a peltier on a Dothan processor. Many steps and precautions can be taken out of this tutorial; however, I chose to present you with the fail safe way of setting up a peltier.

Below is a list of materials used in this guide and where you can buy them. Many of my materials were bought on ebay or simply lying around my workshop, but I have provided a source where all the materials can be bought new.

1.Insulation
a. Conformal spray: www.frozencpu.com
b. Dielectric grease: www.dangerden.com
c. Neoprene: www.angerden.com
d. Pure silicone: Lowes

2. Peltier
a. 172w Peltier: www.dangerden.com
b. Relay switch: www.frozencpu.com
c. Arctic silver 5 and epoxy: www.frozencpu.com
d. 40 x 40mm copper cold plate: www.frozencpu.com
e. Sand paper and sheet glass: Lowes
f. Meanwell 24v 300w power supply: www.power-factor-1st.com

3. Innovatek water cooling system
a. Cool rev3 water block: www.highspeedpc.com
b. Single radi www.highspeedpc.com
c. Eheim 1046 www.highspeedpc.com
d. Temperature probe www.highspeedpc.com
e. Flow rate monitor www.highspeedpc.com

4. Retention mechanism
a. ¼ inch acrylic: www.dickblick.com
b. 1/16 aluminum sheet: Lowes

Water proofing:

I have chosen to take extra precautions while setting up this TEC. This first step is not necessary, but will protect your motherboard from damage by condenstation. If you insulate your peltier properly, then water proofing the motherboard is not necessary! Condensation WILL NOT form if the insulation procedure is done correctly. If you choose to waterproof your board, first you will need to cover all of the PCI/AGP slots, heatsinks, fan conectors, IDE connectors, etc with masking tape. I used a pair of tweezers to rub the masking tape firmly onto the board.




Once the board is masked, two coats of the conformal spray were applied to both sides of the board and adapter.
Picture: conformal coming soon....

Insulation of motherboard and adapter:
I have chosen neoprene for insulating the components because it is firm, closed cell, and very easy to sculpt with an exacto knife. I recommend buying 10 or so blades since surprisingly, the neoprene dulls the blades quickly. You can still cut it with a dull blade, but life is easier when you change the blade often.

Insulation of the motherboard:
I used ½ inch neoprene to insulate the p4 retention mechanism. Slits in the side of the neoprene were cut so that it fits underneath the retention bracket, as well as in the bracket.




Next, cut a hole in the middle of the neoprene where the socket will be.



The neoprene must be cut to the same height as the socket on the motherboard. This picture contains custom retention mechanism for holding on the waterblock. I will show more pictures of this later.



A piece of neoprene can be placed on the back of the motherboard for extra protection. I recommend sealing the neoprene on the board with silicone.

Picture: coming soon

Insulating the adapter:
At this point, if you were simply setting up a peltier with a desktop processor you could skip the following steps. For people overclocking the Dothan, you will need to insulate the adapter. First you should carefully seal the socket on the adapter. I used silicone to seal all the way around the socket and inside of the socket. This will keep condensation out of the socket. I also put silicone around the edges of the adapter which will seal the neoprene onto the adapter.




You should do the same on the motherboard socket. I sealed the edges with silicone and filled the dead space in the middle with dielectric grease.

Cover the adapter with neoprene.


As an extra precaution, I put a coat of silicone around the edges to completely seal the adapter

Putting the adapter and chip on:
All of the socket pin holes must be filled with dielectric grease. This will prevent condensation from forming inside the socket. Condensation can cause two problems. First, the condensation can corrode the pins on the chip and second, the condensation can short out the cpu. Apply the dielectric grease liberally over the socket and push it into the pin holes with your finger.

Picture: dielectric grease coming soon....


Now just place the sealed adapter into the socket and then place the chip into the adapter. We will also need a shim to protect the delicate core. 1/16 th neoprene makes a great shim. I applied a little dielectric grease to the shim to seal the shim onto the chip.

Setting up the peliter:
Before we can set up the peltier we need to lap our cold plate smooth. I used two smooth grades of wet sand paper. The plate was lapped in a gentle forward motion till smooth, and then turned 90 degrees to smooth in the cross direction.



The coldplate was attached directly to the cold side of the peltier by a mixture of arctic silver epoxy and AS5. Of course, make sure that the cold plate is attached to the cold side of the peltier! The red wire should be on the right.



I let the artic silver epoxy set in for a twenty minutes with strong mini vise clamps holding it together.

The peltier and the cold plate need to be insulated with neoprene. Using an exacto knife, I cut out a hole for the peltier and slits for the peltier wires. The inset hole is the perfect size for the innovatek cool rev3 water block to fit securely on the neoprene.




The insulated peltier can now be placed on top of your processor. Put artic silver on your core and drop the peltier right on top for the chip. If you cut your neoprene correctly, the neoprene should center the peltier onto the chip without effort.



Finally drop on your water block and press it on firmly. I used side to side motion and twisting with excessive pushing force to ensure that there was good contact between the water block and the peltier.

You may have noticed in the previous picture that the water block is not secure because the retention bracket is too low for the water block retention mechanism to clip in. This is caused by the extra height from the Dothan adapter, peltier, and cold plate. To fix this problem a new retention bracket was made from acrylic and aluminum. All pieces were cut with a dremel or scored then broken.



Place the new retention mechanism on the board and put the peltier ontop of that.



Finally, mount the waterblock.

To power the peltier, I chose a MeanWell 320W S-320. It a beautiful powersupply that provides 24v and 320w- perfect for a peltier. The efficiency is 86% and thus will save you a little money in the long run.



My goal was to build a quiet computer, and the little fan in the powersupply was too loud. I replaced it with the fan that shipped with the CT-479 fan. It's quieter and moves more air.



The power supply will be turned on and off using a swiftech pump relay switch. This turns on the peltier when the computer is on and turns it off when the computer shuts down.



The pic below shows the two connector to the power supply (top) and the two connectors for pelts. One will be used for the cpu peltier and the other is reserved for a peltier on the graphics cards (probably near future).



a hole was cut out of a back panel for the power cable connector.



The panel was place back on the case.

I custom computer, built from aluminium stock will house this computer. This case was designed to hold both a system power supply and a meanwell for a peltier. Here are pics closed and open. Eventually, I will start a thread explaining how this sytem was built for now, I'll just focus on how it houses the peltier system.



A space above the system power supply was reserved for the meanwell.



Here is the meanwell in that space. Notice it is connected to the relay and the powersupply.



Below is everything with the system open.


Below is with the sytem partially closed

The idle temp is about 3C according to asus probe. I'm using about 1.5v for 24/7 settings. The probe actually reads high (see dothan thread) and the actualy temp is around -2C to -7C, which is about what we would expect with a 172W peltier. Notice this 1.6 Dothan is overclocked to 2.9. This is over 80% overclocked! Pretty nice for a 130 dollar cpu.


Underload the temp is around 16C.



For Super Pi benching, I up the voltage to 1.6v and increase the FSB to 270 to obtain a score of 24.92s.

That looks awesome. I can't wait to see your OC results from this project.

Right on man, that looks very professional and you took your time and made a great thread about it. I am very interested in your results as well since my Dothan stuff is on its way (along with the last parts I need to build my r290 phase-unit).

Looking foward to the rest of this thread.

Added to the sticky. Great job man

nice work on the sealing of that sucker lol

the silicone from home depot/lowes shouldnt be used directly onto the mobo or any pcb or metal parts.
it contains acetic acid to help in curing which is very corrosive (smells like vinegar).

they do have a non acidic silicone but there are other options than silicone you can use.
seal string is a good thing to use in situations like that.

Awesome................you did a good job on the guide. I've always wondered how much sealing goes into TEC preparation. Thanks!

Sticky........very good guide.

rhino56 said:

nice work on the sealing of that sucker lol

the silicone from home depot/lowes shouldnt be used directly onto the mobo or any pcb or metal parts.
it contains acetic acid to help in curing which is very corrosive (smells like vinegar).

they do have a non acidic silicone but there are other options than silicone you can use.
seal string is a good thing to use in situations like that.

Click to expand...

I should have mentioned that. I used non-acetic pure silicone. It takes forever to cure, but it is safe to use on the board

Nice job! Very professional looking too!

Thanks for all your comments! The rest of the thread will probably be posted in a few weeks after I get back from my vacation in Cancun.