My thinking is that both outputs to fail at the same time probably isn't a jack issue as much as something internal.
Check the battery first. Try two just in case. Try a different cord and amp setup too, make sure there's nothing in the chain that is causing your issue. What happens with a standard cord, do you get a blended signal?
Open the cover and check for any loose or broken wires. Was anything loose and recently tightened? Check those things especially closely.
Next is the switch, can you get it to work at all by manipulating the switch a bit differently, i.e. A little side pressure, faster, slower, etc. - is there any change in output when you do these things? Crackles?
Similar approach with volume and tone knobs.
And then the jack. Does it change if you partially insert the jack? Different cable?
A multimeter is your best bet to check all these but from your message I'm assuming you don't have one.
My guess is a bad ground, then a bad switch, then the jack, then the preamp board.
The main Parker site has instructions for the jack under the support menu. Also a few other posts here for where to buy.