Some heatsinks have retaining clips that attach to the other 2 (wider) tabs, I've seen them mostly in OEM systems. Also, I think some of the smaller Socket A coolers can be made to fit; you'll need the ones that clip to all 6 tabs of the Socket A, and cut/grind away the unnecessary part of the clip.

The easiest solution is to having it run in a case where is positioned horizontally and just use the thermal paste as a mild adhesive.
A small cooler could also be attached via epoxy'ing the four corners of a cpu you're not really planning on preserving for "eternity".

I have a intel an430tx (packard bell oem, 0 l2 cache, onboard ATI graphics, 2 pci 2 isa)with a broken tab, i just epoxied the heatsink to a pentium 133 cpu and it has worked ever since

Intel486dx33 wrote:

I have a socket 7 motherboard that has a broken heatsink retaining clip.
Is there any way to fix this ?

Depends. You still have the part that has broken off? If yes, then you can attempt to glue it back. I tried this myself and it wasn't very succesfull.

And if that doesn't work for you, you can always try one of these z-wire clamps.

I have thought about this. It would be hard to get to and you'd have to find out what is right behind that clip in the plastic block - but you could theoretically drill a hole and put a socket/nut in the hole and bolt another block of plastic to it. Just gluing one back on is not likely to be enough given the lateral force involved.

Technically the clip should retain on just a bolt, now that I think about it.

It's kind of an extended hobby task and not very viable if you can get a replacement motherboard.

Desoldering the socket would be at the edge of my skillset and far beyond my patience.

Heatsink adhesive would be the simplest option, if kind of permanent.

You could also wire down the heatsink to the larger tabs with something strong, semi-flexible and not terribly conductive (coated wire of some kind). Sort of an offset clip.