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SX52 heatsink for a PENNY???? — Parallax Forums

SX52 heatsink for a PENNY????

cbmeekscbmeeks Posts: 634
edited 2005-12-13 19:32 in General Discussion
I have been building a NTSC GPU using an SX52 (protoboard). I have been running at 50Mhz and the chip gets a little warm. We brought this up before but I want to push it to 80Mhz and put a heatsink. Well, until I can buy an official heatsink with some thermal grease, I decided to put a penny on the SX52!!! Yeah, I just put it right on. I made sure the penny didn't touch any pins and I am careful not to move the penny.

It seems to be working...lol

The penny is pretty hot. So, I wonder how effective is this temporary fix? Or, could I just get some thermal grease and continue to use pennies until the final project? yes, I am cheap. hehehe

thanks!

cbmeeks

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Comments

  • Guenther DaubachGuenther Daubach Posts: 1,321
    edited 2005-11-23 10:12
    Why not using thermal grease together with a penny! As the surface of the penny is slightly uneven, the grease will reduce the so-called "thermal resistance" between the SX52 and the penny. Instead of a penny, you might consider using a small piece of sheet copper, bent like a U. In this case, I would use some thermal glue to attach it to the SX.

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  • John R.John R. Posts: 1,376
    edited 2005-11-23 14:53
    You could even splurge and use a dime. Beter thermal transfer with the sliver cladding. Or would this be offset by the lack of mass relative to a penny?

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  • PaulPaul Posts: 263
    edited 2005-11-23 16:09
    Remember a penny really isnt copper anymore..mostly zinc I believe. U might want to check the thermal properties of zinc.

    from lrs.ed.uiuc.edu
    1947-1962 3.11 g 19 mm 95.0% Copper and 5.0% Zinc & Tin (bronze mix)
    1963-1982 3.11 g 19 mm 95.0% Cu and 5.0% Zinc
    1983-2002 2.50 g 19 mm 97.5% Zinc and 2.5% Copper (20% lighter)

    EDIT: There is no silver in a dime anymore!! (wow, who knew!): Dimes (and quarters) are 75%· copper and 25% nickle outside with copper on the inside: but yes, copper is still 4 times more thermal than zinc.

    So it looks like a Dime or Quarter would actually be a better choice of coin.



    Post Edited (Paul) : 11/23/2005 5:01:08 PM GMT
  • Mike CookMike Cook Posts: 829
    edited 2005-11-23 16:21
    These might be usable:

    http://www.allelectronics.com/cgi-bin/category.cgi?category=270&item=HS-125&type=store

    need some type of heat conductive glue to attach, was·thinking of getting a few myself.

    Mike

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  • cbmeekscbmeeks Posts: 634
    edited 2005-11-23 19:17
    Mike Cook said...
    These might be usable:

    http://www.allelectronics.com/cgi-bin/category.cgi?category=270&item=HS-125&type=store

    need some type of heat conductive glue to attach, was thinking of getting a few myself.

    Mike

    Thanks, but 40 CENTS!!! I'm not made of money!!! lol

    Seriously, thanks guys....I currently don't have any thermal grease/glue so this is about as good as I can do. I will put a quarter on and see if it's any better.

    But for prototyping, the penny goes a long way! hahaha

    happy thanksgiving everyone!

    cbmeeks

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  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-11-26 16:18
    I went into a local computer store look for some printer ink today and passed by their customized computer components.

    There I saw very tiny heat sinks in day-glow blue aluminum. They seem to be for cooling your RAM chips, so they come in sets for about $5USD [noparse][[/noparse]$150 Taiwan dollars].

    I looks like one would fit nicely atop the SX-48 or SX-52 and create quite a bit of convection. They are about 3/8 inch square and the same in height with 8 to 10 fins.

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  • SeanLSeanL Posts: 10
    edited 2005-12-03 22:26
    A coule hours ago I was testing some code on a project and things starting heating up, literally. Amongst the rats nest of jumper wires on my·SX tech board,·I managed to acccidently wire up not 1, not 2, but 3 short circuits. It didn't take long before the smell of the rosting chip filled the air. The·SX got so hot it sizzled when·I licked my finger and touched it. After correcting my wiring 'whoops' everything was working fine. Amazingly the sx seeming to have come out unscathed. It made me think about this thread.

    I·just happened to have some change sitting on my desk and·I couldn't stop thinking about using a penny for a heatsink, not that I really need one. Use a Dremel (or simular type tool) smooth one side of the penny. This would increase the·contact area between the·SX and the penny to improve heat transfer, even if you do end up using thermal grease. I'm guessing the side with Lincolns face would require the least amount of work. His head looks bigger than the monument, but there is less lettering. Depending on which speed you run the Dremel, you could probably save 5 or 10 seconds of work. You might as well be lazy if you're going to be cheap smilewinkgrin.gif. Now take some·scrap wire·and solder·it to the monument side of the penny to make fins. I think a multi-strand wire would be better than a solid core.·You could spread the·individual strands out and each would give a greater surface area over the solid core.


    I don't·actually·know how well it would work but it's my 2..err 1 cent
  • John KauffmanJohn Kauffman Posts: 653
    edited 2005-12-13 19:15
    Wouldn't the foil from a stick of gum be even cheaper & give more surface area?
  • cbmeekscbmeeks Posts: 634
    edited 2005-12-13 19:32
    Either that or some real aluminum foil. You could flatten it really smooth...just make sure it doesn't touch any of the pins.

    You could make a large foil disc and put a penny on top to hold it down. Now THAT's come cheap heat sinks...hehehe

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