Got speeding ticket on slauson ave thinking it was 50mph zone going with the traffic flo but really 35mph..?

So basically I was over by 15mph, but a couple weeks later found out that my cars speedometer (entire instrument cluster) was failing and got it swapped completely by the nissan dealer. I got the invoice stating "instrument cluster failure, replaced". Should I try to get my ticket dismissed? what approach would be nice to the judge?