I purchased a very nice and great sounding used but newer DSL40CR that came with the compatible 91016 six-button footswitch, but unfortunately it does not work. 

The standard footswitch that also came with the amp works fine. And I also checked 3 separate working cables, so it seems to be the footswitch itself. When you plug it in, it sort of uncontrollably cycles through channels and all six blue lights illuminate on the switch, but then nothing. Totally dead. 

I really was pumped at being able to set up four pre-sets, clean through lead and a few in between. Now I'm stuck with just the two playing live. 

That footswitch seems to be unavailable anywhere. Is anything else that is available compatible?

thanks!

Andrew