I have a hgt 155, I've searched and found a few posts about this, but nothing specific.

My rev counter works intermittantly, I can sometimes get it going with a thump to the console, but lately even the violent approach isn't working.

Any ideas as to what I could do? Ideally I don't want to fork out for a new speedo/rev counter display, but is this the only option?

9/10 sticky rev counter = dashboard. Sorry for the bad news but it is quite common.