dash board display completly dead but car works fine?

On starting the car the dash board does not come on. No rev counter, no speedometre, no petrol gauge or temperature gauge. No indicator lights. When I turned off the engine the display light for the mileometre stays on. I pulled the fuses out and checked them all ok. A pulled out a 5 amp fuse (fuse ok) and the light that remained on went out and when I pushed it back in and turned the car on the dash board works fine everything came on. This problem started a few weeks ago and has been intermittant ever since. Any ideas?