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Removing potentiometer and making a direct connection? Answered

want to remove those potentiometer ir order to attach a RsbryPie 3 heatsink to make the IC cool. IT'S a PAM8406,and on it's max load it's getting really hot. So have to apply a heatsink. So is there any​ way to remove those potentiometer and connect those line directly, i mean I'm newbie in this thing. So need some help, thanks in advance.

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Sayan_trex

8 months ago

somehow i managed to put a resberry pi heatsink into the gap and attached that heatsink to another big heatsink. So it's totally fine now, and also btw my project is done.

IMG_20171224_215027.jpgIMG_20171225_142752.jpg
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seandogue

9 months ago

I'd modify the heat sink, and reduce the demand. If that's not enough then you need a board rated for higher power. A general rule of thumb in electronics is to keep loading under ~70% of max for durability and reliability.

You *could theoretically move the pots, but their position with respect to the chip may be crucial for minimizing noise and maintaining stable operation.

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seandogueseandogue

Answer 9 months ago

PS> are you using passive cooling? If so, I'd recommend adding a fan to circulate air. The efficiency of a passive radiator (ie a simple heat sink) is dictated by the temperature differential. If air is stagant, the ambient temperature near the heat sink begins to approach that of the heatsink itself and so its ability to dump heat is dimished.

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Jack A Lopezseandogue

Answer 9 months ago

Hey, what do you think about just submerging that board in mineral oil?

I have heard rumors, also seen pictures of,

https://duckduckgo.com/?q=motherboard+cooled+by+mi...

personal computers submerged in mineral oil, for to cool them.

However, for something like this tiny amplifier board, mineral oil might actually be practical, since the total volume needed to surround it is so small.

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seandogueJack A Lopez

Answer 8 months ago

You'll still need to dissipate the heat. "inert" oils can be used as a liquid heat transfer agent but they don't magically get rid of it. I'd be more inclined to upgrade the baord if it's being run on the ragged edge of operability.

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Jack A Lopezseandogue

Answer 8 months ago

Well, for this to work, the oil has to somehow move heat from the (hot) IC to the (cooler) walls of the container holding the oil and the circuitboard, and I am guessing that "somehow" will be a combination of conduction and convection.

I mean, it would be getting really elaborate if some kind of fan, or stirrer, was needed to keep to keep the oil moving around.

Regarding the container for the oil plus circuitboard, I was imagining an aluminum can type beverage container might work well for this.

I admit, this arrangement is probably going to be ugly looking. Basically a beer can, with a bunch of wires going in and out of the top of it.

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seandogueJack A Lopez

Answer 8 months ago

Yes, instead of a simple fan, you'd need a pump to keep fluid circulating. And likely a directed "jet" to keep it circulating in the area of consideration. You'd also need a way to release it from the "walls" of the fluid tight container. Which means a heat sink and another circulator, this time at least a fan. Since it's oil, and since oil has a high heat capacity, it would be even better to use forced release by using a peltier to drop the wall temperature, encouraging transfer of the heat. Overall, it sounds to me like an unnecessary pita.

So like I said, a fan and modified heat sink would be the most reasonable solution (for most instructables applications), if one was adamant about using an under-rated driver, or being even more sensible and realizing that if one is pushing the device so hard that it's at the edge of failure, that a higher rated component is a far more sensible solution. Buy or design and build something rated for twice the expected load. That way it runs cool and there's no need for complicated solutions to prevent it's failure and keep it doing its intended mission.

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steveastrouk

9 months ago

When a chip like that is overloaded, it isn't designed to take a heatsink.

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iceng

9 months ago

If I understand, you want to remove the pots and wire bypass them to make a space for attaching a heatsink with silicone heat transfer grease to that plastic IC..

If the pots are throughole just mount them on the underside..

Now how do you plan to firmly press and hold that heat sink to the plastic IC..

Understanding that a poorly applied heatsink will actually cause the plastic to get hotter and fail... That Si grease is used to fill in micro spaces where plastic is not in firm contact with the metal heatsink...

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Jack A Lopez

9 months ago

The footprint for those potentiometers is an isosceles triangle, so you might be able to unsolder them, and then put them on the back side of the board through the same holes. Then maybe you would have enough to room to put a heatsink on that IC.

I mean, the wiper terminal of the pot winds up connected to the same part of the circuit it was connected to previously. The other two terminals of the pot get flipped, but that is not a big deal because, you can just adjust the pot to correct that.