I Can Multimeter Things Again!

Okay, so I have a ton of multimeters — I think around 5. I’m not really sure why; I think almost all of them I’ve gotten for free except for my favorite one, a Sinometer VA18B, which has a ton of functions and can also send data via USB.

But, I left a battery in it and the terminals got so corroded that they were destroyed. 🙁 So I thought I could quickly solder a new connector to the board.

Rule #1 of electronics: DO. NOT. TAKE. SHORTCUTS.

I didn’t want to take the board out of the housing as shown above, so I thought I could just desolder the existing wires and feed the new ones in. I ended up lifting the pads, making those spots that I was supposed to solder completely useless. Furthermore, I accidentally had my iron temperature set too high, so I was melting a lot of the insulation (the high temperature also caused the pads to lift).

So, I fixed the problem by basically tacking the wires onto the sides of components that were electrically close to the original holes. Mechanically, this is a very bad idea; the connections are very brittle. Take a look at this mess:

And to top it off, the replacement 9V connector I had was too big for the plastic slot, so the battery cover didn’t fit on very well at all. Ugh.

So, morals of the story:

  1. Don’t leave dead batteries in your devices.
  2. If you’re going to do rework on a board, keep the iron temperature as low as possible.
  3. Take the time to undo the extra few screws to have better access to the board. Otherwise, it’ll take you more time in the end and you’ll end up with a worse result.
  4. On the plus side, my multimeter does in fact work again, so I’m happy about that. 🙂 🙂 🙂

2 Responses to “I Can Multimeter Things Again!”


  • Hi!

    I have a same multimeter but unluckily its burned down one of the resistor and I can not find any circuit diagram. Would be so kind and read me the R33 resistor value? It’s just located near VR2 potentiometer. Thank you for your help in advance.

    Have a nice day!

    Zoltan

  • Just remembered about this… It’s a 100K resistor in case anyone is wondering.

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