CEM DT-9989 multimeter repair

[Mr Evil]

Recently I picked up my CEM DT-9989 multimeter, and noticed that the back was loose. I thought that maybe the screws had somehow worked themselves out, but 5 of them just span around when trying to turn them in either direction. On unscrewing the one non-loose screw and removing the back, it bacame clear what had happened: the screws screw into plastic pillars, 5 of which had snapped off.

The meter was an ex-display model, so I don't know what sort of treatment it had before I got it, but it has mostly just sat on my desk in the 8 years I've owned it, never being dropped or roughly handled, so I don't know what caused the plastic to fail. All 5 pillars snapped off at the same place, just above the PCB. It's disappointing that they didn't use brass inserts in the first place, given that this was an expensive piece of kit, even when not-new.

Since there was still a few mm of each pillar remaining, I tapped the holes in them and fitted some brass standoffs in their place. M3x12mm (+6mm male threads) fitted exactly. I used epoxy on the male threads to make sure they can't unscrew when I take the back cover off again.

And now it's back together securely. Maybe there's something wrong with the plastic itself, and something else will fail in the future, but for now it's useable again.