M-Audio Prokeys 88 Premium Piano. No sound in headphones and in audio out. Help Me Please!

most are, (volts, amps.watts and pin wiring)

there is no standard on wall warts. ever, for sure world wide.
no thing told Prokeys 88 what is that?
ahh my wild guess is gee you posted to computers and is not
it is a music keyboard (cheap)
Prokeys 88 SONO? what is it exactly the SONO uses standarded USB power pack like used on cell phones.


the sono runs 2 ways with USB power pack
or connected to any PC with USB cable (5vdc is USB)
the non sono 88
uses a 12vdc power pack
I say use 12vdc pack 2 amps. web cameras CCTV IP cams sold vast these.

the non sono page 4 clearly states (gee first google hit too)
12vdc, 500mA (1/2 aMP OR MORE) AND CENTER PIN PLUS.

https://www.manualslib.com/manual/293107/M-Audio-Prokeys-88.html?page=4&term=12v&selected=2

EASY peasy japaneezy./

e.g.

http://www.ebay.com.au/itm/Global-AC-Adapter-4-M-Audio-Prokeys-88-Stage-Piano-Charger-Power-Supply-Cord-PSU-/260991184879

Test if the headphone jack has sound.

This is a midi lockup problem with conflict somewhere in your setup. Have you switched midi local off on the keyboard?

The resting (centering) of the PB wheel has a problem. It is LIKELY mechanical in nature. You will have to open the unit to investigate or take in for servicing. If you open it yourself, have two people to help hold the two parts of the shell to avoid damaging the ribbon cables when opening.

It is NOT likely the keyboard is "killing the speakers"... OR the headphones for that matter.

I suspect the problem is bad switch contacts in the headphone jack that cut off the speaker line outputs when headphones are plugged into the pro keys. These jacks are, to put it bluntly, JUNK... they are EASILY damaged by pulling the cable plugged into them sideways. You will need to service the unit.

Here is a site:

http://www.m-audio.com/index.php?do=support.faq&ID=5157184a3df533e664f6dfaef620d6b2

Essentially you hold down the + and - buttons while powering on the unit. Hold them till it is obvious it is resetting.

Check the power supply.... I have seen these fail on this unit. Low voltage would cause this type of problem.

I have two of these. First thing check your power adapter for output. Just because LED's are on doesn't mean there is correct voltage... There is no reset button... Cycling power serves to reset it.

ALSO check the power input connector... sometimes those get intermittent and break connection due to vibration and initial current surge when turning on.

here's a link for places to start calling around