Motorboating is usually caused by defective bypass caps or lack of tube shields. Be sure you replaced electrolytic caps. In Zenith's there is another problem. Radios were made to be used with "G" type tubes. If you use metal tubes pin #1 has to be grounded. Only problem being Zenith often left out a pin #1 contact on their tube sockets.
Norm
:my p0rbulm i have recaped mod 10s470 radio and i still
:have the problum can you help dennis
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