new heatsink

[emosun]

there is a traic on my packard bell 810/820 motherboard that is getting very hot , like stove top hot. The triac is directly next to the cpu heat sink and has it's own very small heat sink. 

I attempted to put a fan over the heat sink but it's still hot regardless. So I'm thinking the heat sink it's using must not have enough thermal mass to actually be effective. 

Do you think a larger heat sink with a fan would be more effective in cooling it? I just don't want it to burn out

[TheRandomness]

Mind taking a picture of the area?

[TheBean]

need pictures

[emosun]

4 minutes ago, TheRandomness said:

Mind taking a picture of the area?

 

it's the triac heatsink next to the cpu socket

[TheRandomness]

Just now, emosun said:

it's the triac heatsink next to the cpu socket

-snip-

Doing what you've already done with a fan will already be enough to keep it within operating temperatures (below 125 C), but if you're still worried you can always get a larger heatsink.

[emosun]

1 minute ago, TheRandomness said:

Doing what you've already done with a fan will already be enough to keep it within operating temperatures (below 125 C), but if you're still worried you can always get a larger heatsink.

I'm just curious why it's so hot. the other triac you see on the board with a heatsink near to top left , is barely even room temperature.

[TheRandomness]

1 minute ago, emosun said:

I'm just curious why it's so hot. the other triac you see on the board with a heatsink near to top left , is barely even room temperature.

Since it's so close to the CPU socket I wouldn't be surprised if it had something to do with CPU voltage, which tends to fluctuate a lot.

[mariushm]

That's not a triac. A triac is used mostly with AC voltage and there's no AC voltage on a computer motherboard.

 

The chip on that heatsink is most likely a linear regulator or a voltage controller with integrated transistors or maybe even mosfets (though not sure we were at that point when socket 7 existed)

Basically, that chip's job is to take in 5v or 3.3v from the power supply and spit out 2.5v or 2.8v or whatever a socket 7 processor required, throwing the voltage difference away as heat.

It's normal for that heatsink to be hot, and that chip should tolerate up to maybe 100 degrees Celsius and that heatsink could be up to 80-90c - looks like the motherboard desingners also expected that the cpu fan would also move some air around the heatsink to help.

 

From the picture, that chip looks like it's a plain TO-220 style package, so you should be able to find loads of heatsinks if you want to replace the existing with a bigger/better one.

Here's a starting point: https://www.digikey.com/short/31v3m5

Use the filters to make sure heatsink is not wider than the space your old heatsink uses, then check the depth (from the chip to the right, how big the fins can be) then pick as high as you want as long as it won't interfere with other parts.

The smaller the "thermal resistance" value, the better that heatsink is at taking heat out from the chip and spreading it over its surface, from where it can dissipate in air.

The first in the list above -the cheapest- are obviously not good enough... just from picture i would guess you'd need something with a value less than 15c/w, maybe even less than 10c/w

[Unimportant]

@emosun

Most TO-220's can go up to 125 degrees C.

Since you don't state how you measure the temperature, it's also worth noting "feeling" is a very bad method. 65 degrees C will feel like scorching hot to the touch, while it's pretty cool for your average semiconductor.

[Unimportant]

7 hours ago, mariushm said:

That's not a triac. A triac is used mostly with AC voltage and there's no AC voltage on a computer motherboard.

 

The chip on that heatsink is most likely a linear regulator or a voltage controller with integrated transistors or maybe even mosfets (though not sure we were at that point when socket 7 existed)

My money is on linear regulator. A switching regulator would require magnetics, and a freewheel path (big schottky for example), neither of which are to be found in the picture. That explains why it runs so hot, and as such, it's totally normal.