The mechanical vibrator does make a noise while operating, but it is way different from the condenser hum. If you disconnect the speaker and turn-on the radio, you will hear the vibrator buzz. It is normal, and usually not audible while the radio speaker is working over it. In fact, when the radio is cold, the speaker does not "kick-in" until a couple seconds later. So when you turn it on, you hear the vibrator first, and then the speaker a bit later. If the speaker also hums and volume control has no affect, if the filter condenser. Although, if you are still able to tune the stations, it might not be the filter condenser. When it is bad, you get no stations just the hum at constant volume. If the radio has not been re-caped before, you'll need to replace all the condensers anyway. This will likely take care of the issue (if any).
When you replace your original 3-in-1 filter condenser with the 3 electrolytic ones, make sure that you follow the proper polarity as indicated on the new caps (+ is actual +, - is actual -, and not your positive ground). If you don't, you'll have to buy new caps like I did ๐
Also, here is some more useful troubleshooting info: