Gauge light do not work...

I have checked all fuses even replaced the cluster voltage regulator & the cluster lights do not come on.

The seat belt light comes on, the turn signal lights, radio lights, a/c heater lights and console lights all work.
Do you think the circuit board could be bad... the cluster is the original 82 that came in the car.

Don't know if related but the RPM gauge & Fuel gauge do not work as well... all other gauges work.

Any info on what to do next is greatly appreciated.