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Fixing a broken PLCC (FPU) socket

Posted: 04 Mar 2026 16:55
by dml
While extracting an FPU, I noticed a crack in one corner of the socket. This probably happened the last time the chip was inserted.

plcc1.jpg

Unfortunately this causes the socket to separate at the break with outward pressure from the IC and the pins don't contact properly.

So I had two options. (1) replace the socket or (2) try to fix it. Given how tricky replacement is with the surface mount type, I opted for (2).


I decided to make a tensioning strap from solder braid.

plcc2.jpg
plcc3.jpg

To get tension, I tacked one end to a part of the socket some distance from the break with JB kwik weld epoxy and let it set.

plcc4.jpg


I then pulled the braid tightly and held it with pliers, soldering the free tinned end on top of the first tinned end, glued to the socket.

plcc6.jpg
plcc5.jpg

I added some epoxy to the inside edge of the cracked corner and let that set.


Posting this in case anyone has the same issue and decides to give it a try.

Re: Fixing a broken PLCC (FPU) socket

Posted: 05 Mar 2026 00:18
by mikro
Many years ago I used a wire tie for the exact same purpose. The advantage was that I could really tighten it to my liking.

Re: Fixing a broken PLCC (FPU) socket

Posted: 05 Mar 2026 08:19
by rubber_jonnie
mikro wrote: 05 Mar 2026 00:18 Many years ago I used a wire tie for the exact same purpose. The advantage was that I could really tighten it to my liking.
Yes, I was going to suggest a tie wrap, they're good for getting tension on things.

Re: Fixing a broken PLCC (FPU) socket

Posted: 05 Mar 2026 08:23
by dml
If this doesn't work out I'll change it for a cable tie. I only have the bigger kind handy so the braid was a much better fit. Will see how it goes.

Re: Fixing a broken PLCC (FPU) socket

Posted: 05 Mar 2026 09:44
by exxos
I 3D printed a square to go around the outside. I was half thinking of getting some made in metal at one point.

Re: Fixing a broken PLCC (FPU) socket

Posted: 05 Mar 2026 09:48
by dml
I can confirm this morning the bodge worked well - swapped the IC twice without the repair splitting open again. The ICs are testing good in that socket.

Re: Fixing a broken PLCC (FPU) socket

Posted: 05 Mar 2026 10:30
by rubber_jonnie
Also, I've been trying out UV activated resin as a means of repairing plastic damage and it's very strong and resilient, definitely useful for this sort of thing provided the UV can get in and activate it.