Jumat, 20 November 2009

Analogue Volt Meter, Revived

Sometime, we in our workshop just throw away damaged things into a drawer. The same goes with this cheap Heles AVM, after a few use it's just don't swing anymore, goes into one drawer some years back. When I bought old capacitors recently, I need to see needle swing on the meter, Digital Volt Meter is no swinger :). So, in line with my principle 'use whatever you have' , old Heles is my operation target.

The problem turns to be a loose copper wiper and wobbly shaft of the disk. Thewiper was just fastened by 2 plastic pins that was melted by a solder to clamp the wiper down. Well, this is a good plastic design practice for non moving part, for moving part you need larger pins or a long rib.

So here are the fix, add a screws to the shaft and wiper. Now the needle swings !.

But the fix brings new problem..as always, a solution creates new problems :(. There is no room for the screws, so a 30 minutes fix became 1.5 hours... Bottom of the casing is drilled, then cut a jelly cup bottom (remember..use whatever on hand..), epoxy-ed them..voila!..

Another problem, the meter just does not want to stay put , so add 4 rubber pads, cut from black foam I have in my garage-double tapes them..

finito..and still fit in the old box ..., mother earth and my wallet is saved again, just 2 things I have to throw away..the casing cut out and a jelly cup with no bottom..now lets swing!

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