Nissan Repair: tach bouncing, flexible circuit board, pencil eraser

Question
Hi - The tach in my 1996 Almera 1.4 suddenly started bouncing. I had previously been at the distributor but have since replaced it. When I push on the clock setting stem it goes to normal, but only while it is held! Is this simply an internal short? I have read it could be spark plug cables - I've been at the plugs but... (thanks for the great work)

Answer
Mark,

If you press on the reset and the tack works properly leads one to think the problem is with the instrument cluster.  I would remove the cluster and clean the contacts at the harness connector with a pencil eraser and then blow off the eraser dust.  Clean both the harness connector and the recepticle in the cluster.  Also, make sure the screws are tight.  Usually, the tach is held by two screws that interface with the flexible circuit board on the back of the cluster.  I like to unscrew then a turn and then lightly tighten them back up to get a good connection.