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digital dummy
11-18-2009, 05:28
Good morning,

I purchased a kit (dtech) on ebay.

It's new. I read on one of the posts all the extras I need to nstall it, but I have searched, and can't find the post.

basically I got the pmd, the cooler, and a 6' cord.

I think someone mentioned something about some sort of silicone to go between the pmd and heat sink (maybe it's not silicone...I think they said to get it at a computer store)

anyway, my new toy is arriving tomorrow, so I would like to make sure I have everything ready.

thanks

DD

DmaxMaverick
11-18-2009, 08:26
I won't go into where to install it, there's enough about that handy on many recent threads.

The cooler/driver should be in stalled very solid. Vibration-free is the goal. The kit should include some thermal conductive paste or pad. I recommend paste for optimum efficiency, but the pads work, too. If the kit doesn't have the thermal solution, you can get thermal paste at any computer store, and some Radio Shack stores. Most small appliance/electronic and motor/generator repair locations will have it, also (a good shop will apply it for you, if you ask). The best stuff is "Micronized Silver (oxide)". There are some silicone based compounds available for extreme heat applications, but by the time the temp gets high enough to take advantage of this range, your truck is probably on fire (read: unnecessary for your application), and it is less thermally efficient. Clean both surfaces with rubbing alcohol or non-lubricating electronic/contact cleaner. Don't use brake parts cleaner, as many of them are not friendly with plastics. Ideally, only a very thin paste coating is necessary, between the FSD transistors and the heat sink surface. No more than is necessary to fill the ultra-fine grain and gap spaces. Usually, a B-B to pea size drop is sufficient. It should be spread evenly to ensure complete coverage. I use the edge of a credit card (you can use anything similar, the edge needs to be straight, sharp, and clean) to trowel the paste in an even, unbroken coat. Once the surfaces are mated, don't allow them to twist or move around, and tighten the mounting screws evenly, like you would head bolts. The key is even pressure. Use lock washers (spring type, not stars) and some Loc-Tight to ensure constant torque and security. They don't have to be torqued super-tight, just enough to ensure a solid mating, and a tiny bit more to allow for thermal expansion/contraction over time. The thermal conductive solution is ONLY for the mating surfaces between the FSD and heat sink. Do not use it between the heat sink and mounting surface on the truck. It isn't an adhesive or sealer. It is only to ensure maximum thermal conductivity between the FSD transistors and heat sink.

digital dummy
11-18-2009, 08:44
thanks for the info.

received my kit a day early. The compound was in the kit.

However, there is some confusion:

on the main instructions that came with the kit, it says to use the compound.

But there is a supplemental small piece of paper that says to use a gasket ( a waxy type of gasket) that was included.

Does any one have any idea which one I am supposed to use?

thanks

DD

DmaxMaverick
11-18-2009, 10:16
Did the kit include both, the pad and paste? If so, I suggest using the paste. If only the pad, use that (make sure it's a thermal conductive pad, and not a "gasket"). It isn't that critical, but I have my 'druthers'. If you can post a pic of the kit contents, it would be helpful. If the "gasket" has a label on it, please relate that, as well.

digital dummy
11-18-2009, 13:24
yes, the kit came with both. Like I say, I think the small piece of paper saying to use the gasket was an afterthought.

It is almost like wax paper, precut, and predrilled to the same dimensions as the back of the pmd.

The concern I have is that it has a lot of small creases in it, like it was crumpled up while packaging, and the folds may not lay 100 percent flat.

If the paste has always worked, i think I will stick with the proven stuff. Can;t seem to find anyone else who has posted anything about this gasket.

DD

the small sheet says:

The DTECH DT76301 PMD comes with four mouting screws. The short screw must be used in the recessed area of the pmd. They msut be tightened to 20 lbs torque. Be sure to place the included mounting gasket between the mounting surface and the PMD


There is not printing on this seal or gasket.

Sorry, don't have a camera to take a picture.

DmaxMaverick
11-18-2009, 16:54
I dunno, then. The only reason I can think of is some customers were somehow screwing up the paste method. If they recommend the gasket, perhaps you should use it. And, use only the pad, no paste, as both will be counterproductive. Thermal conductive pads should either be like aluminum foil or very, very thin foam, double sided tape. I don't know about the "wax paper". If it isn't a thermally conductive material, it can't be of any help, and likely worse than using nothing. Metal to metal is better than an insulator, which will reject heat, rather than conduct it. However, Dtech has made claims in the past that their driver has no issues with heat. If heat is an issue, it will surely fail within the warranty period in the absence of thermal conduction. If you have doubts, give them a call. Maybe they can tell you why.

JohnC
11-19-2009, 11:04
..They msut be tightened to 20 lbs torque.

I hope it really says "20 in-lbs torque..."