Making weird plugs. Staring with the rim. If you are lucky you find a matching piece of water pipe. In not, use a strip of sheet metal. Usually not a full circle, as the plug often have a positioning ridge. Find a wire for the pins. For the RT-70 it was 1 mm installation wire, for the HP-432 I used the pins of a PC drive power connector. To be sure, spray the plug with a contact spray like Servisol. Cover the plug with thin plastic foil, for example from a one-way plastic bag. Place the rim over the plug and plastic. Stick the pins through the plastic.
Fill the plug to be with a mixture of expoxy glue and fine sand. Let cure and remove the plug. Remove the plastic and attach the wires.
Using a magnet from the voice coil mechanism of an old 3.5" harddisk (left).Separate from the iron frame with a knife (hammer on the blade of a disposable knife). If the brittle neodynium magnet is not broken yet, break it in 2 more or less equal peaces. Remove the content of the latch (a ceramic magnet between to iron poles). Replace the ceramic magnet with the two pieces of neodynium magnet. Reassemble.
