I just received a used NRD-525 from a dealer on ebay. All functions work
except the main tuning knob - it doesn't change the freq at all. The
up/down buttons work and the direct entry works. (The lock is not on.) I
tried reseating the boards but nothing seems to help. Am I overlooking
something simple? The unit supposedly worked 100% okay when shipped, so
possibly something came loose in shipping.

Greg