[morzh]

Obviously if you were able to put the signal through the radio, the coils should be Ok. The 78 tube - you could try to change it, but not likely it is the culprit. Assuming you did in fact put the signal via the antenna input and were able to peak it by the antenna xfmr trimmer.

If the assumption is correct, it is likely the antenna itself. Try a different one, or reorient theexisting if it is directional.

Also if the proper stations appear at their respective frequencies at the lower dial part, the oscillator is tracking properly.
So if you told us everytning, my vote is for the antenna.