hp xw8400 workstation Heat Sinks

[parvardigar1]

Hello

This is an unexpected difficulty. I have two heat sinks that I cannot screw down into the thread area.

That would be any one of the eight bolts pressing down on one and another holding the heat sink presses down backing off the screwing motion 

- then attempting to screw in again and so forth. The photos show that the heat sinks are established into the appropriate notch and one would expect in the usual, normal fashion, that one could simply press down and screw the bolts into the slot, into the frame. What's to do?

[SDH · Accepted solution]

Been there, fixed that...

If you look at the xw8400 motherboard from above and below (see pics below) you can see that there are no attached threaded press-fit inserts along the undersurface of the motherboard. If the motherboard has slid in its positioning even a bit then the heatsink attachment screws can be misaligned, and then you can't get them started in their attachments (built into the metal case beneath). Don't try to force them... risk of cross-threading... don't ask how I know.

My advice: Loosen each of the 8 motherboard screws a little so the motherboard is a bit loose, align things up properly with the heatsinks off, retighten the 8 screws, and then attach the heatsinks. My recollection is that the theading on the heatsink screws is #6-32, the same threads HP used on the silver hex head case screws on the outside rear of the case. I used to use those to help align and firm up the motherboard attachment to the case for dual processor xw6400s if I was using only one processor/heatsink. You can use a few of those case screws temporarily through the motherboard's heatsink attachment holes to help align the motherboard before you tighten down the 8 other screws... then switch in the heatsinks which will now be perfectly aligned.