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I have an old computer monitor, and the back lights in it have simply "burnt out" and died from old age. So I am making up a LED array to slide in the back of it and to give me a new back light.
But I need a power supply to feed the LED array. The only source that had the right voltage and amperage, was a power pack, but I needed to extract it's internals so I could remount and rewire the the transformer and rectification circuit into the computer circuitry.
Oh those jolly little power packs - how we love them, that is until you need to rewire them or extract the components from them.
There are two ways to open them - IF you want to reuse the case, my best friend recommends using a deftly applied ball pein hammer to crack the cases along the joint line. He should know - he opens and repairs hundreds of them.
It's actually a really brilliant method - to "smack" along the ultrasonically welded joint line... with a hammer and crack it. A solid seam makes a cracking noise - a kind of ring of sorts; and a "cracked" seam makes a flat toneless note - sort of like glass without and with a crack. It seems best to hit the joint along the side that has the inner lip - so it pulls away from the outer lip.
I started off on the completely opposite track of simply wanting to open them for parts, and
I have always had a hard time getting them open, so my methodology has developed along completely different lines.
I stated off by trying to hack and crack them open using hammers and screw drivers and having all sorts of dramas....
My final resolution - is to have made a cutter - a special cutter that fits into a drill press and is made from commonly used parts, and it cuts by the heat of friction.
But I need a power supply to feed the LED array. The only source that had the right voltage and amperage, was a power pack, but I needed to extract it's internals so I could remount and rewire the the transformer and rectification circuit into the computer circuitry.
Oh those jolly little power packs - how we love them, that is until you need to rewire them or extract the components from them.
There are two ways to open them - IF you want to reuse the case, my best friend recommends using a deftly applied ball pein hammer to crack the cases along the joint line. He should know - he opens and repairs hundreds of them.
It's actually a really brilliant method - to "smack" along the ultrasonically welded joint line... with a hammer and crack it. A solid seam makes a cracking noise - a kind of ring of sorts; and a "cracked" seam makes a flat toneless note - sort of like glass without and with a crack. It seems best to hit the joint along the side that has the inner lip - so it pulls away from the outer lip.
I started off on the completely opposite track of simply wanting to open them for parts, and
I have always had a hard time getting them open, so my methodology has developed along completely different lines.
I stated off by trying to hack and crack them open using hammers and screw drivers and having all sorts of dramas....
My final resolution - is to have made a cutter - a special cutter that fits into a drill press and is made from commonly used parts, and it cuts by the heat of friction.
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Signing UpStep 1How to make the cutter.
With all my years of engineering experience, although this design "fell out of the sky" being it was more or less the very first parts I grabbed from the screw bin, it's actually about the very best design that one could hope for for this project.
The bolt is a 10mm x 0.75mm pitch (or 0.8mm) threaded high tensile bolt, which is the same thread as most bicycle axles - and the fine thread pitch enables the nut to tighten up very tight and make lots of clamping force to hold the washer firmly.
The washer is what is called a "trailer washer" or a "fender washer", and I think it comes from the time when every one in Australia used to once upon a time, build their own small trailers, and they used this type of washer to hold the mud guards or fenders on.
What makes this design so good, is that the hole in the washer is a very close fit onto the bolt shaft - thus making it inherently run true to the shaft.
The bolt is a 10mm x 0.75mm pitch (or 0.8mm) threaded high tensile bolt, which is the same thread as most bicycle axles - and the fine thread pitch enables the nut to tighten up very tight and make lots of clamping force to hold the washer firmly.
The washer is what is called a "trailer washer" or a "fender washer", and I think it comes from the time when every one in Australia used to once upon a time, build their own small trailers, and they used this type of washer to hold the mud guards or fenders on.
What makes this design so good, is that the hole in the washer is a very close fit onto the bolt shaft - thus making it inherently run true to the shaft.
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