So I know this is an old subject but might help some people I did some research I bought a hd400 on reverb.com for peanuts because of this broken preset rotary switch and I am planning on fixing it so far everything works except that I can still use the up down left right button next to it but I'd like to have it all working and many replays are correct fullcompass sells a lot of these switches just search line6 pod hd 400 rotary switch and or ENCODER popped up and read the description there is only 3 that popped up as Rotary there was a lot of other stuff but first 3 result are what you need and it's the 2nd of the 3 u can kinda tell it's smaller and more uptodate looking in the description it says for line6 pod hd300 hd400 hd500 and hd 500x this is the PRESET REPLACEMENT PART AND IS $6.60 Imsure you can get them for under a buck if you have the Part number but good luck finding it I tryed to post screen shots so here's the link good luck and as always your voiding warranty the second you open up done familiar with soldering and electric basics ATLEAST don't pick around and get shocked or killed don't linger around cuz it looks pretty sinside ,
don't be dumb fix what you need and get out of there like a navy seal
Good luck
http://www.fullcompass.com/prod/196120-Line-6-24-12-0006
