Buying a used S4 what should I look for?

[rob24g]

Buying a used S4 from someone around my area. Does anyone have a checklist or can help me out with what I should check for when I meet up to buy the s4?

I don't have traktor pro and neither does the guy selling it to me, so I don't know how I can check to make everything works before I buy it... I don't want to buy it then find out 2 hours later that some knobs or sliders dont work correctly.

Any suggestions would be helpful, thanks!

[enrico]

you'd need a computer with traktor to check the controller is fine, to ensure each signal is doing what is supposed to.

i'd check, at least twice, every button, knob, fader, jogwheel, to make sure they all work. pay special attention to the smaller buttons on the fx units and on each deck.

i'd also check the connections, specially that the usb connector has not been abused.