Alert chipset heat sink not detected system halted error message

This is a relatively common problem in the Dimension 4600c. The small, fan-less heatsink for the Northbridge chip (a memory/video-to-cpu communications chip) is held down by a spring, which is anchored by two small wire loops soldered to the motherboard at locations marked "HS2". The spring completes an electrical circuit between the two wire loops. The spring puts a substantial force on the minscule bit of solder holding the loops to the motherboard, and was a poor design.

If a loop breaks off, the circuit is broken, which tells the BIOS that the heatsink fell off. To fix this, you need to 1) secure the heatsink to the chip, and 2) reconnect the circuit between the two "HS2" locations on the motherboard. I have sucessfully used this solution. This solution will not necessarly stand up to a lot of abuse if the Dimension's enclosure is frequently opened and closed to replace other components such as RAM and hard disks.

0) unplug the computer.

1a) Recover the heatsink, spring, and loose wire loop. Discard the spring. Get:
- a fresh tube of thermal paste from Radio Shack or other electronics supply store,
- some epoxy,
- a round toothpick,
- about six inches of insulated 14 to 20 gauge solid copper wire,
- electrical solder, flux, and a soldering iron,
- and a box of cotton swabs.

1b) Using pure alcohol and lots of cotton swabs, clean *all* of the existing thermal paste off of the Northbridge chip and the bottom of the heatsink. When both are dry, apply a dab of paste to the center of the Northbridge chip. Use a round toothpick like a kitchen roller to spread the paste evenly across the small raised center square of the chip.

1c) Apply small daps of mixed epoxy just outside of the four corners of the raised center of the Northbridge chip. Place the heatsink onto the Northbridge chip, centering and squaring it as best you can. Press firmly to make good contact with the thermal paste. Allow epoxy to dry.

2a) Firmly seat one or both detached wire loops into their mounting holes at the "HS2" locations. While pressing down on the loop, apply a small dab of epoxy to one end of the loop to secure it to the motherboard. Allow epoxy to dry.

2b) Strip the ends of the copper wire, and bend the wire so that it can reach around (rather than over) the heatsink to the two wire loops. Solder the ends of the wire to each loop. Knowing how to solder is an exercise left to the reader. "Use head main ting": don't drip solder onto the motherboard.

You can now plug in the computer and restart. The BIOS and/or OS may have saved the error state and return a different message about the heatsink issue. You may need to reboot a couple of times to allow the BIOS to notice that the "HS2" circuit is (hopefully) now complete. When you've sucessfully booted the machine, shut it down and gently close the Dimension's enclosure.

Fixed a pc when heatsink fell off when a spring broke off ,was laying inside the computer.

Clean with a little rubbing alcohol to remove any dirt or thermal paste, Get some thermal TAPE and carefully put one square on, and stick in back on. The tape is VERY thin so be careful. but works very well to hold the heatsink on the board so the chips don't overheat.

Have you moved your computer lately? It sounds like your heat sink has failed or come loose. This is what keeps the processor from over heating. You will have to take a look inside the computer to see if maybe the hold down spring popped or something.

Check/secure motherboard CPU heatsink clip.

I had the same problem; wire loop to hold end of heatsink retaining wire had come unsoldered, started getting the same alert message on my Dell 4600c.

Shook the case a bit to deposit the loop on the floor, then resoldered it to the motherboard. To avoid removing the motherboard, the plastic was removed from the loop to facilitate soldering the thing back from the face-up side, at the right height to get the same spring tension on the heatsink.

Works again!!

Cheers,
David

Far less complicated route, especially if you lose the U Pin:
Just take a bread tie, paper sleeve removed, and thread it through the holes in the motherboard (like threading a needle) then twisting the ends together to make a loop on the chip-side. Take the spring-loaded heatsink and hook the tension arm into the bread-tie loop. Circuit is now complete again, all fixed. No soldering, no money spent, no epoxy, nothing complicated.

Can you test the continuity of the clip with an ohm meter?

What is heat sink

I lost the wire loop to hold down the heat chip what else can I use to replace the wire loop ?
Dave