Im going to convert my DeWalt charger fom 110v to 240v as i got sick of lugging a step converter around. Now i have found two guides which uses the exact model of charger i have but they have partly different solution. I would like to know more of what could be the reason they they did what they did.

It is clear that the transformer thats powers the charging circuit can handle 240v. Both of the guides replaced the 200v 220uF which is totally i understand, that capacitor would pop under 240 VAC and should be replaced with a value above the peak 400v + should be fine. 

Now the similarities end, the [First Guide][1] changed the capacitor and added 2  0.33Ohm  5W resistor 

[![enter image description here][2]][2]

The [second guide][3] did not speak in english so i did not understand what he was saying but basically i think he add a varistor on the main input and instead of using a resistor im not sure what that black thing is (ceramic capacitor?) but why would he add a capacitor? if you look closely look on either of the videos you might notice that that slot is labeled "R" so i assume a resistor is supposed to be placed there (instead of a jumper)

[![enter image description here][4]][4]

Can someone help explain to me what could they be possibly doing ? Sadly i dont currently have my charger so i cant take more detailed pictures of the circuit. But maybe someone may have an idea based on past experience.

  [1]: https://www.youtube.com/watch?v=rc5ieIGUYBo
  [2]: https://i.sstatic.net/zV5d3.jpg
  [3]: https://www.youtube.com/watch?v=7DJRJk5MQrU
  [4]: https://i.sstatic.net/vpQ84.jpg