Zalman MFC2 .. went BANG...then sparks...

[antipesto93]

yesterday i turned on my pc..and all the fans connected to my MFC2..would not stay on...they went on off on off...like there was not enough power to the fans

then 20 seconds later i say some a spark and a bang come from the fan controller!
i opened it up and i think the ' 74hc 151d ' IC chip blew up...as it has a hole in it!.....why...?also there was a red led on the boared that started flashing just before the bang

any help would be appriciated!

[noxqzs]

The chip you listed is an 8-input multiplexer. It basically takes 8 inputs and is usually controlled by 3 control bits (think binary 000, 001, 010 = 0, 1, 2) . Without looking at the schematic, it is hard to tell what the purpose of the logic is, but usually it is used to cycle through multiple inputs so they can be fed to one output. For example, you only have one LCD indicator for temperature, but 8 probes. Based on the control bit addressing, you could cycle through all possible probes to show on one display output, one at at time.

[antipesto93]

yeah that makes sense...becuase now i cant control any of the fans..:(
does anybody know where i could buy that chip?
thanks

[AlabamaCajun]

Jameco, Alltronics or Digikey. It is CMOS and will die from static so ground you and the soldering iron. The HC is high-speed Cmos meaning you need the HC version. They generally cost 1-3 bucks so get 2.
For a chip to get the packaging blown like that means that a 12V or higher source likely hit one of the probes.

http://search.digikey.com/scripts/DkSearch/dksus.dll

I'm guessing you need the first in that list if it's a normal sized chips. The rest are all 300mil with are the small versions.
Note the solder though legs on these. If' yours are soldered to the face of the board then you will need go with the SOP package not DIP.

[Bomber5000]

As Alabama mentioned, that IC shouldn't explode like that given normal operation.

I'd give your card and probes a thorough check before you mount the next IC. I assume that if you have a soldering iron you probably have a multimeter that you can probe around to see if anything else went up causing your part to go poof.

Maybe unhook the fans and all external parts and power it up and check regulators, diodes, etc. I'm not sure what that particular board uses for a power source, but if it regulates 12V down to 5V for the logic, those regulators would be a good place to start =)