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Old 19th Jan 2019, 12:10 pm   #1
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Join Date: Apr 2007
Location: Hampshire, UK.
Posts: 1,514
Default A new door for a B&O Beosystem 10

I bought a tired-looking B&O Beosystem 10 portable radio cassette at the audiojumble last year, it is one of the few B&O products of the 'interesting' era (mid 60s until the mid 90s) that I'd not previously owned.

As everyone knows, these were contract manufactured in Japan and aren't really a 'proper' B&O (much like the Beocenter 2000 / 2002 / 2200 etc isn't), but there are a few details in there that suggest that the Danish factory had a small hand in it - the design of the battery terminals is identical to that of the Beolit 400 > 707 range for example. When new they were a bit too expensive for what they were and rather under-marketed, so in this country at least they are now few and far between.

With many faults fixed and the cabinet tidied up as well as I could, it was only the absence of the door over the minor controls over the front that was spoiling it. It is common for this to disappear; the hinges are flimsy and once it is flapping about it tends to get in the way of the cassette door so they get taken off and lost.

The rest of the centre section of the machine is made from high gloss black plastic so this was the obvious thing to make a new door from. However, I couldn't find any of the right finish and thickness so I had to think again. In the end I came up with the side panel from a scrap Sony music centre, which was made from a basic black moulding compound (similar to the stuff that Wheelie bins are made from - ABS?). It had been painted silver on the outside in the factory and was black on the inside - ideal.

The first thing to do was to determine the size. Measuring the cassette door gave the width, after that it was easy to scale the height using catalogue pictures. The basic shape was rough-sawn out, then milled to the exact size and required squareness. I used the lip that was formed along one edge as the basis for the hinges, milling most of it away to leave two 5mm square blocks at the two bottom corners. Short lengths of stiff wire were then fused in with a soldering iron to form the hinge pins.

The door is held shut by a little catch of a familiar type; it works like an 'on / off' button taking an alternate state each time it is pushed. In the 'out' state two little claws open, releasing the barb-like peg that engages inside. Until I started this I hadn't realised how many variations on the size of the peg there are, so I couldn't cut a pre-formed one off anything else to use. However, careful measurement of the catch gave the size required, so I milled out an 8mm strip of the same material I'd used for the door and carefully filed it out of that. The material is soft so it didin't take very long.

Positioning the peg was easy. I put the set on in its back and located the peg inside the catch, square and in the middle. A small amount of cyano-acrylate glue was then applied and the door closed, so as to 'pick up' the peg in the correct position. Being identical materials the two parts bonded quickly and firmly; the door now worked as intended.

To get the deep, 'piano black' finish I was looking for I first rubbed down the painted surface with fine oxide paper in soapy water. The existing paint gave a smooth surface to key to and meant that a primer coat would not be required. Aerosol black paint of the craft type (rather than car paint - B&Q sell it) was then built up in many fine layers. To finish with, a thin layer of yellow was then applied to act as a guide coat. Once dry the paint was then rubbed back with the same type of fine oxide paper and soapy water that had been used before. The disappearance of all the yellow confirmed that all the surface had been flatted, this is a good way to avoid missing bits or going through. After that, cutting compound was used to bring up the shine and wax polish to seal the surface.

The result makes the set look pretty good again. It will never be mint, but its a useful and attractive set now which I really like listening to. The third photo shows all the details I have mentioned.
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