What do? Digital outputs seem to work fine, analog output 2 (follows a different path) also works but the main analog out and the headphones out don't (same path for both)

 

I can't think of any synth where a menu option will disable the headphones output. The audio outs, maybe; but headphones no.

I'd open it and look for loose or unclipped connections hoping to find something easily addressed. Do you have a schematic/wiring diagram for it already?

 

I did and I looked inside, no visible signs of damage but the thing is all stacked boards. Too many ribbon cables that I'm really not comfortable touching, always have bad luck with those. Looks relatively clean inside.

Analog output 2 works fine but it doesn't follow the same signal path as the output 1 and headphones output. Guy I got it from agreed to reimburse me so I'll just send it back and he'll have his friend look at it. If he can fix it I'll just pay for the repair and buy it again, if he can't I'll wait for another one to pop up at around the same price (paid 215€ shipped, bargain price for an sd90 these days)

 

are you trying to replace an old one you have a bunch of work already done with? I doubt that one will be coming back to you anytime soon. I'm not sure why someone would sell something and not tell you analog out #1 does not work; like you wouldn't notice. But it sounds like the seller already knew this, to me.

 

Not really, it's my first one.
Seller said it was in storage for 2/3 years, I asked him to rest the digital outputs/inputs and they work fine. I assumed he'd test the analog ones too but apparently not. Don't think he tried to scam me though. He'll reimburse me tomorrow morning (bought it via bank transfer) and I'll send it back to him within the end of the week. If he can get it fixed great, if not I'll just wait for another to pop up since he said he might keep it and just use it as a digital mixer at home if he can't get it repaired. There's only one for sale on eBay EU and it's much more expensive plus it looks trashed.

Would've solved my soundcard woes on Windows (not osx sadly) at least, was thinking about setting my old thinkpad for digital recording somewhere on top of my JV-1080

If anything I'll have wasted 10-20 bucks in shipping costs