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How to isolate the ac/dc converter of my display

  • Hey there!

    I want to use the ac/dc converter (and also the display interface board) of my display. But I want to isolate it properly so I can place it on the backside of the lcd panel that’s made of aluminium and the solder joints won’t touch it. The frame of the hole mirror will also be out of aluminium.

    I bought plastic sheeting for this purpours but I’m not sure if can just glue or tape the board on it.
    Could there be a problem with heat development or something else?

    Here 2 pics from the display + ciruit boards and the plastic sheeting
    0_1518983351727_rsz_display.png 1_1518983351727_rsz_plastic.png

  • I’m going to preface this by stating that I am not an electrical engineer… Modifying electronic devices & removing enclosures to expose live conductors is dangerous. Know the risks! I wouldn’t plug this in without an rcd or similar device being between the mm & your source of mains electricity.

    The main issue there will be your ac terminals. There are iec standards which tell you the correct clearance required, based on a whole range of parameters. I’m not qualified to give you an actual distance, but if it was me then I’d be looking to do at least the following:

    Use some kind of ‘stand off’ to physically stop the bottom of your board from touching the metal case. Think of the type of standoff you would use on a motherboard for example. Thesr can be fitted to the corners of your board.

    Use a thicker, solid insulation… That sheeting you’ve shown would be easily punctured by a sharp bit of solder at the bottom of your board. I’d use a solid piece of plastic underneath it as well (got any old plastic lids from a takeaway container?)

    Finally as you’ve cracked open the case of your monitor consider if there is a chance that you now have metallic elements which could (under fault conditions) cause a shock if touched. Is the chassis earthed?

  • While I work in IT these days, I still do and have been and electrical engineer. Safety is obviously the key here, I would certainly not be willing to put that in my kids room for example without taking the proper precautions. Plastic sheeting is not a proper precaution. You can buy cheap cases from fleabay that would do the trick, or buy a sheet of 3mm Perspex and manufacture a case using hot glue and a dremmel to cur the holes as required. To fix the PCB to the Perspex use standoffs as already mentioned, which also cost pennies.

    In many countries, insurance policies will not pay out if there is an incident with modified devices unless you have them certified by a qualified engineer. In most cases this does not cost much, but it is something to think about.

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