I just picked up a '96 240sx a few days ago and the speedometer will cut in and out periodically. If I tap around on the cluster it will cut back on so my guess is that a contact point on the circuit board needs to be re-soldered. I've searched up and down and only found threads about it being the speed sensor, but since it works in and out I don't think that's the problem. There could be a short in the wiring, but again I don't think tapping on the cluster would fix that.
I read this post:
#/f/showthread.php?t=355077
but it's talking about fixing the tach for a kouki cluster, not the speedo for a zenki cluster. Would this be the right way to go about doing the speedo or what else could it be?