Help - Casio synth power problem

hi all. My Casio CZ-230S synth (1980's) will no longer run with a power adapter, but works fine on batteries. I have a sentimental attachment to this keyboard! and since it takes 6 D batteries to run, a monetary need to fix it as well.

I think it was most recently being used with an adapter that wasn't original to the synth. It seems the original power adapter was a 9V 850mA. It's possible I was using a 9V supply with a lower mA rating. Would this allow it to work for a while, but then ultimately cause it to break? It's the only thing I can think would be the problem.

Is this something I can fix myself? I have worked with electronic components before.

thanks for your help. Any direction would be appreciated.

Get a proper supply and try it. The only damage would have been to the other supply. 9V, 1000mA is the ticket.

If the PS is ok-

Sometimes the jack can get a broken trace and not work. What happens if you wiggle the jack with the plug in? Also, the jack can get so dirty that it wont work.

Resoldering the traces around the jack can work for the first thing, Spray contact cleaner can work for the second.

I got a dead CZ101 for $12 and resoldering the dc jack traces brought it back to life!