Fitting Replacement Risc PC Rubber Feet

by David Thomas on

If you have a faithful Acorn Risc PC kicking around you might have found that the rubber feet on the bottom of the case have started to crumble, like mine:

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In some cases the rubber feet can even liquefy and leave you with a wonky computer sitting in a pool of grey goo.

You’ll be pleased to know that you can lever off the old ones and replace them with a new set of Bumpons (that’s what they’re called) from 3M.

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The specific ones you want are 3M Bumpon SJ5023 in grey. They’re 20.5mm² wide by 7.6mm high. The datasheet is here. I bought my replacements from an eBay seller. Note that the greys seem harder to find than the black and clear variants. [2021 update - RS have them: https://uk.rs-online.com/web/p/anti-slip-pads/0236537/].

Once you have your replacements, start removing the broken feet. Avoid damaging your antique computer by working a blunt knife in at the corner closest the edge. Then push up to lever the old foot out.

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This is made easier since the holes for the case locking pins go right through the case and leave a void under the foot; the bumpon’s flat base never entirely adheres to the full square.

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Once removed, clean the old glue off using some isopropyl alcohol. I used a toothpick too for the harder gunk.

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Cleaned:

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Then you can peel off the new feet/bumpons/tapered squares/trapezoidal prisms from their backing paper and fit them:

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