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just bought a Audigy 2 NX USB soundcard was quite surprised to find that it runs pretty hot! Does your's too ?? Afterall how much power could a little card consume ? The tiny adapter is rated at 5V 1.5A . So I decided to find it out myself and was even more surprised to find a current drain in the order of 900ma!
Thats almost 5W of power! That got me curious and the covers came off right away. I wanted to see what produces so much heat and consumes so much power.Right off the bat I noticed that near the DC input was a little inductor (L1) that was the hottest thing on board, followed by a regulator(LD33 - probably a 3.3v reg). Not only that, a pair of filter caps right after the inductor
were running hot too(that doesn't sound very good).Besides that, another regulator (LD18 - probably a 1.8v reg) somewhere else on the board was relatively warm too.
But the chip that caught my attention was the Sigmatel codec. I didn't expect that one to be so hot. Other chips were noticeably warm to touch if not hot.
Here's a list of all major chips I found on board.
Sigmatel STAC9460S - Codec
JRC 4556A - Headphone output
ST MC33078 - Line level output/input dual opamp. Total 4.
Philips UDA1334 - Low Power DAC
Philips ISP1581BD - USB device controller
Creative CA0186 - DSP
Cirrus Logic EP7309 - High-Performance, Low-Power System-on-Chip Enhanced Digital Audio Interface
ST M29W400BB - 4Mbit Flash Memory
ST LD33 - 3.3v regulator (?)
ST LD18 - 1.8v regulator (?)What still intrigues me is that these chips are not power mongers, in fact they are 'low-power' devices yet they manage to draw that much current all together!
These chips are very typical in portable players and I have yet to come across one that runs so hot.
Does that sound normal ? Do you think something's not right ?
Follow Ups:
This sounds like the power supply is oscillating at a high frequency, that could cause significant core losses in the inductor and large current flow through the caps which would heat them up. Its probably a switching type supply, but they are SUPPOSED to have well filtered DC coming out, this sounds like its NOT well filtered.Of course it could be caused by the board taking a lot more current than it should which is clobering the regulation of the supply.
BTW hot electrolytics is NEVER a good sign, they will go bad very quickly if they are hot, so that definately sounds like something is not the way it should be.
Hi John,
thanks for you reply.
Oscillation was my first thought. Actually I did try with battery too but since I only had rechargeables and only a 4-cell holder I couldn't manage to get a constant supply over 4.8v so couldn't do a good test but I intend do that soon.
The ISP1581 and STAC9460 chips are usually the hottest. Possibly why would a USB controller and a CODEC get hot ?
Both those chips disipate about 0.7 watts acording to their spec sheets, thats a pretty hefty amount of power for such small chips, I would expect them to be quite warm. If they are so hot you can't touch them then there is probably something wrong.
what I still haven't found is whether this is a problem with all NX's out there or was it just mine ?
John, your and mine guess was correct. It was the psu! Tonight I did a good test with a battery. The caps and inductor showed no or very little sign of heating. The other two chips I was concerned about were also just reasonably warm.Btw, current drain was 640ma at 5.4v.
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