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Replacing a missing pin on a PLCC IC

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dml
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Joined: Wed Nov 15, 2017 10:11 pm

Replacing a missing pin on a PLCC IC

Post by dml »

So in an unrelated PLCC drama (see earlier post), I lost a pin from this FPU.

fpu1.jpg
fpu1.jpg (455.38 KiB) Viewed 1201 times

I would normally throw this in the 'dead parts' bin - but this one has an interesting bug which helps me verify my FPU testing tool. So it would be nice to hang onto it.

I decided to try replacing the missing pin. This isn't super easy because the pin broke off flush with the package. It will involve some drilling. I opted to drill from the underside because it will be easier to support the new pin from behind with an epoxy filler.

fpu2.jpg
fpu2.jpg (372.35 KiB) Viewed 1201 times

To replace the old pin, I picked the leg of a potentiometer. It's definitely a bit wider than the original but it's also not flimsy, which should help. I can always dremel the sides of the pin later to make it thinner.

fpu3.jpg
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fpu4.jpg
fpu4.jpg (408.68 KiB) Viewed 1201 times
fpu5.jpg
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fpu6.jpg
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fpu7.jpg
fpu7.jpg (188.08 KiB) Viewed 1201 times

Finally, some epoxy filled in the cavity behind the pin.

fpu9.jpg
fpu9.jpg (435.81 KiB) Viewed 1201 times




I'm not recommending this as a thing to do - just posting for entertainment purposes. Unless you don't have any other option, better just throw it away and save the socket :D
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rubber_jonnie
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Re: Replacing a missing pin on a PLCC IC

Post by rubber_jonnie »

I've done similar before, definitely worth a go if the IC is known good.
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russellnash
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Re: Replacing a missing pin on a PLCC IC

Post by russellnash »

That is quite a sophisticated repair, well done.
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