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CS USB Multimeter temp calibration and fuse replacement Victor 86b

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  • CS USB Multimeter temp calibration and fuse replacement Victor 86b

    After an "episode" using the multimeter on my car I blew a fuse. Anyway, I didnt notice the blown fuse until I was ready to roast some beans. So under the house on dirt after a few beers i thought it was a good idea to take apart the multimeter.......mmmm.
    I was in a rush and after running some wire across the fuse (I know...) I began to quickly screw it back together a bit impatiently as I was already behind schedule. I put one of the screws into a whole in the circuit board and screwed but it did not really tighten, as it should. That was because I had screwed it into an adjustable pot and destroyed it! After that, the multimeter went a bit crazy, reading out a bizarre negative temperature, something like negative 57c and would only "climb" in a negative direction.

    Short version is I got a 20k pot (98c) from Jaycar and a new fuse (40c) , I replaced the small fuse (240v, 500ma) and soldered the pot in. The following bit is what I wanted to share (for those who dont think their temp is remotely right or if they blow a fuse like me), I had to calibrate the temp by simply turning the pot I had replaced, I boiled some water and set the multimeter to read around 99c. Shoved the probe under my tongue later and got a reading of 36.6 after 1 minute so close enough for me.
    You need to undo 5 screws on the back of the unit before you get to circuit board (one of which is the battery cover - mine ended up in the dirt somewhere) Once your in my my main tip is to only undo four screws from the circuit board when separating it from the face of the unit. 2 screws are located at the bottom corners and the other 2 around 4cm from the top corners.   When separating the board from the face you have to gently pull it apart as the dial knob on the front face if firmly pressed in a rotary switch. I was stupid enough to undo more than just the 4 screws and the little internal parts of the rotary switch fell out (that is another story).
    Here are some pics:
    The new pot in place, the dead original one sitting next to it.

    and the hole (top right) that i should never have put screw through!

    I am pasting this as FYI and not trying to encourage people to rip apart their functional Multimeters.