Beginner working with surface mount passives.

[Meaker]

I want to change the value of a built in resistor network as shown here:

http://i4.photobucket.com/albums/y143/Meaks/Resistor_zps7b90fafa.jpg

This sets the output voltage and the spec sheet shows that a reduction in the resistor to ground raises the voltage.

To test I have used a pencil to draw over the resistor and lower the value (multi meter to test the new value) and it works as expected. This is not however ideal as a permanent solution.

What tools and technique would I be best off getting to do a low volume of these or is it just not practical due to the size and density of the components?

[KJDS]

You need a decent soldering iron, flux, solder, tweezers and probably a magnifier.

I think it's an 0402 size which isn't too bad to do. I'd recommend a soldering iron from JBC, Metcal or Pace. You'll struggle with almost any other. Depending on your eyesight, either a magnifying lens or a microscope so you can see that you have a good joint.

[NickAmes]

You can lower the resistance by tacking on another resistor in parallel to the first (essentially the same thing you did with the pencil lead). Use the formula for resistors in parallel (https://en.wikipedia.org/wiki/Resistor#Series_and_parallel_resistors) to calculate the value you need.

You need a decent soldering iron, flux, solder, tweezers and probably a magnifier.

I think it's an 0402 size which isn't too bad to do. I'd recommend a soldering iron from JBC, Metcal or Pace. You'll struggle with almost any other. Depending on your eyesight, either a magnifying lens or a microscope so you can see that you have a good joint.

Second the recommendation for flux and a good set of tweezers. Flux is the essential ingredient in getting a good joint, and high quality tweezers will save you frustration. However, you don't need a fancy soldering iron to do this kind of operation. A Hakko FX-888 should be fine. I've done similar work with an even lower quality iron.