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Thread: M2-ATX Catches Fire is 1st 3 minutes!!!

  1. #21
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    Quote Originally Posted by gregas
    I don't see it as a value product now!

    Zootjeff, you seem to know about some of the problems, care to elaborate? Feel free to speak engineer, I am an EE.

    Thanks,

    Greg
    The Mosfet that burns up is an SO-8 N-Channel Mosfet. If I could read the markings on the pictures I could tell you all about it. One problem with the SO-8 package is that it has a few units too many units of thermal resistance from the Junction to the Leads of the package. On top of this, the M2-ATX does not provide much copper to take away the heat on this MOSFET. There are traces that run away from it and not a copper pour/plane. Then it the heat has to go to vias, where it probably does go to the plane, but at that point, there are several more units of thermal resistance.

    I bet if you had a fan aimed right at this mosfet you would not have this flame-up problem, but you have to really get some air flow over it.

    -Jeff
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  2. #22
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    Quote Originally Posted by gregas
    It was Q9, an 8-pin part. Does this part have a history of failure? Here is a picture of it.

    Attachment 32102
    Can you get in there and read the markings on all the SO-8 Parts?
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  3. #23
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    Quote Originally Posted by zootjeff
    The Mosfet that burns up is an SO-8 N-Channel Mosfet. If I could read the markings on the pictures I could tell you all about it. One problem with the SO-8 package is that it has a few units too many units of thermal resistance from the Junction to the Leads of the package. On top of this, the M2-ATX does not provide much copper to take away the heat on this MOSFET. There are traces that run away from it and not a copper pour/plane. Then it the heat has to go to vias, where it probably does go to the plane, but at that point, there are several more units of thermal resistance.

    I bet if you had a fan aimed right at this mosfet you would not have this flame-up problem, but you have to really get some air flow over it.

    -Jeff
    Thanks. I figured it was a FET. I'll check the markings later. It seems like a really marginal design. That worries me since it's likely that when I start my carputer that it may be ingesting really hot air for a while. Given the car environment, it needs a robust thermal design, not a marginal one! I'm sure that I could improve the situation by silver epoxy'ng a heat sink over all four FET, but that's a just a band-aid. Plus I'd have the plastic package thermal resistance inline.

    At this point I'm think of returning the case as well so that I can get one that fits a bigger (and better PS).

    Greg

  4. #24
    FLAC evandude's Avatar
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    It's really too bad they didn't over-engineer with their choice of FETs. if running an epia can cause them to heat enough to burn out at ANY realistic ambient temperature, then it seems that they definitely should have used much beefier ones; the fact that they're SO-8 in the first place is a bit worrisome, I would have expected to see something more along the lines of a TO-252 package or similar (like the one in the lower-left corner of that picture), which has much better heat sinking capability when soldered to a board; perhaps the fact that they stuffed the M2 into the same footprint as the M1 (while demanding about 75% more power out of it) might have influenced their decision to use the smaller SO-8 transistors which are clearly not up to the task.
    But don't take it from me! here's a quote from a real, live newbie:
    Quote Originally Posted by Viscouse
    I am learning buttloads just by searching on this forum. I've learned 2 big things so far: 1-it's been done before, and 2-if it hasn't, there is a way to do it.
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  5. #25
    FLAC is for flaccid parksgm's Avatar
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    Quote Originally Posted by rsd212
    Im glad you've had a good experience, but you shouldnt order a product and have to toss the dice as to whether or not yours is going to explode or not. I know this happens to every complex device on the market, but there just seem to be way too many exploding M2's with so few of them actually being sold...
    ...and when the M2s go, they seem to frequently take the motherboard/other devices with them.

    By disclaimer, I am a disgruntled M2 user who had a very similar experience There's a corresponding thread with pics of my unit and another mp3car.com users here: Another dead M2-ATX...)

    I'm glad they replaced my unit under warranty, but the frequency with which the M2 ruins systems in ridiculous. After reading this post, there's no way I'm hooking my warranty replacement up to another motherboard...it's still NIB, and I'm selling it!

  6. #26
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    Quote Originally Posted by parksgm
    By disclaimer, I am a disgruntled M2 user who had a very similar experience There's a corresponding thread with pics of my unit and another mp3car.com users here: Another dead M2-ATX...)
    Gee, I wish I'd seen that! Yes, it's the same FET.

    Shouts at self: Use the search, NOOB!!!

  7. #27
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    This is rather interesting. I've been using a M1 for over a year now and have had no issues.

    How much has the design changed from the M1 to the M2?
    Jan Bennett
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  8. #28
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    Fire and car = ka-boom!

    This can't be good.
    New Car PC Build list in progress

  9. #29
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    Quote Originally Posted by Red GTi VR6
    This is rather interesting. I've been using a M1 for over a year now and have had no issues.

    How much has the design changed from the M1 to the M2?
    The M1 has a lot of DPAK FETs instead of the SO-8s. That is why the current ratings went down on the 3.3 and the 5 on the change from M1 to M2. But the 12 went way up. The 12 is actually using half DPAK and half SO-8s. When you're selling something into this market, you have to make trade-offs. The problem is the marketing is out you to convince everyone that this is exactly what you need.
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  10. #30
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    I can understand that completely.

    Most people will see the same power ratings (or there abouts) and a cheaper price, which one will they go for?
    Jan Bennett
    FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

    Please post on the forums! Chances are, someone else has or will have the same questions as you!

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