Boss DD6 repair help! (DC jack)

[had_hc]

Hi, i have a problem with my DD6 where it'll make popping sound and turning off and on as it goes, when i use the DC jack. but when i use battery, its fine. I looked inside the dc jack and saw that it is oxidised/corrode. tried to rub it off using sandpaper but to no avail.

So, i decided to replace the DC jack. but the problem is, when i desolder the DC jack, i saw that there is 5 PIN at the DC jack! what does the other 2 do? i only have the 3 PIN DC jack, can i use it as a replacement and how?

thanks!