replacing heatsink

[clamrade]

Hello,

First post. Brief introduction is in order. I'm an electrical engineer from MN. Computer is an Athlon 1.4GHz, ECS K7S5A, Radeon VE, and the usual, standard stuff.

This all started when my sister got a brand new Dell, which was ultra quiet compared to my computer. All of a sudden, the same old fan noise became intolerable. So, mimicking the Dell design, I took out the CPU fan on the heatsink and ducted the air flow to the fan on the rear of the case using a crude duct made out of cardboard box (from a X-mas gift box). This helped, especially when the fan was mounted to blow out.

Adding a 10ohm resistor to the fan helped further, albeit a 5C increase in CPU temperature, which now peaks at 64C with case temperature at 30C. Panaflos will be next, when I order parts from newegg next time.

I also want to switch to a copper heat sink, but I'm concerned whether I can simply swap out the heatsink. It's got the stock AMD heatsink/fan that contacts the CPU by some sort of double-stick tape. At the very least, I want to replace that double-stick tape with some Arctic Silver. AMD engineer once told me that removing the heatsink after it's been fused is not good. I'm not sure I quite buy that. I can't see how it can't be scraped off with a razor. At the same time, obviously, this is a one way street: if it won't go back on, I need a new processor.

So, does anyone have experience with removing/replacing a heatsink that's been fused to the CPU by this "double-stick tape?" BTW, where would be a good place to buy fans, heatsinks, and such? Newegg shipping kills.

Thank you for you help. It's good to be here.

Jin Kim

[MikeC]

Welcome to spcr! I think that goop is waxy thermal interface material, not glue. It melts on first use as the CPU heats up and the stuff kind of seeps into the irregularities between the surfaces. There is some bonding action but I would be surprised if the adhesion was so strong as to make the HS impossible to remove without damaging the CPU. If you're willing to risk, you might try easing the thing off slowly from one corner with something like a wooden tongue depresser or popsicle stick -- I would say screwdriver but that is awfully hard & you're very close to the CPU core. Maybe best with the motherboard removed?

I think there was someone else here asking the same question a while back -- maybe he did it & can tell us if it was safe? Anyone?

[ChiefWeasel]

This 'double-stick tape' is normally called 'frag-tape', at least it is at the HardForum. Try a search there for it a see what comes up, im sure there will be lots of people wanting to know how to remove it. I would have done a search but the search isnt working at the mo! (As it often isnt at [H]! )

[hyum]

if it's an athlon, i doubt it is thermal tape as thermal tape normally is not effective enough. it may be phase-change thermal material. it's easiest to remove when it changes phase, which is when it's hot. so if it's phase-change, an easy way to remove it remove it quickly after you turn your computer off and it should be in liquid state at least for a little while (consitancy might be like thick thermal grease).

as for reusing the heatsink, it should be fine if it was thermal tape of thermal phase change interface material- as long as it's properly cleaned before re=mounting. if it's tape or phase-change, you can use a pen knife to lift it off the tape or phase-change carrier, and rub the heatsink off with rubbing alcohol. then apply the new thermal grease before re-mounting.

[clamrade]

Just did it. HS came off easily, the thermal compound behaving more or less like chewing gum. The residue was scraped off with finger nails and wiped clean with acetone. The compound was eventually replaced with Arctic silver. However, I was disappointed to notice only 1C or so difference.

The old Antec (smartfan) went and was replaced with a Panaflo. The rear fan grill was also removed. All in all, the CPU runs cooler and much quieter.

Final mod would be to temperature control the fan. I'm going to try a simple thermistor and another controlled by a MOSFET. I can update if anyone is interested.

So, what would be the high comfortable CPU temperature? So far, 76C didn't crash the system.

[rcmontgomery]

I would definitely try to stay below 80c, I think the Athlons can go to 90c but you are really shorting the lifespan of the chip. I'm also in Minnesota.

Rob