Instrument panel help??

I have similar problems with my '70 Duster 340. Pulled the dash to find why my oil press. and temp gauges were on and off, also had right turn signal ind. light out. (although fender ind. worked fine) Checked all bulbs, all working, cleaned all contact surfaces on PC board, and put it all back together. NOW, I have only very dim dash lights and very dim turn signal lights(checked at night), no movement on ammeter with engine running and an oil pressure gauge that gos to about 20# and stops. I ran a new wire from PC board to a good ground, no change. Temp. and fuel gauge seem to be OK. Does anyone have any idea what all these problems would have in common? Thanks and I will get back if I (you) can solve it. Oh, the radio also quit!