Easiest way to get a "wiped" D-50 to output a tone?

[TwoWheels]

Hi:

I have a friend who left their vintage D-50 with me. I was giving a battery error and none of the patches look right (no meaningful names). I replaced the CR2032 (which resolved the error message) and have tried to get it to make a sound, but NADA - just some hiss when I turn up the volume. The "LOCAL" is "ON".

I'm not at all familiar with this device, and I have neither a memory card nor a midi interface. Is there a quick way to edit a patch to be SURE it "should" be generating a tone? I'm familiar with old analog synths where I would just set up a VCO, but this one I'm not getting any of the terminology.

HELP? I just want to find out if it works at all.

Thanks,

Dave