DJM 800 XLR & RCA Outs (major issues)

Hey there, thanks in advance for any assistance!

- Pioneer DJM 800, bought used + heavy usage since, no warranty - 

[Given that I've already had a shop look at this, I know sending it to Pioneer is going to likely be the only option... so I'm mostly asking this to see if it's even worth doing that or if the mixer is simply toast beyond its limited functionality]

So while just playing music through it (not even actively DJing), my mixer essentially died: left channel (XLR & RCA) has simply awful popping and gunfire noises, right channel (XLR & RCA) is almost usable but there's some annoying static in the high-end. Also seems the headphone out (cue) doesn't work at all. Booth outs still work fine (so it's technically usable), as does the recording out.

Any ideas what's causing this, and are these issues all directly connected?