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Adobe Acrobat   " drawing.PDF " drawings within this website. If you need the FREE Adobe Acrobat Reader, simply download it from the Adobe Website by clicking on the Adobe box immediately below:

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This is a photo of the 6V6 for 4H4-C substitution Service Note from National. Click on the picture for a larger, higher rez version.


 The FSNs and other pages listed below are available in .JPG format. Click on the FSN number.


Subject: Receiver(s): Notes:
FSN-30.1 Manual changes vs prod. NC-300 NOV 15, 1955
FSN-30.2 Manual changes vs prod. NC-300 tough to read-email

me for fill-ins

FSN-30.3 Manual changes vs prod. NC-300
FSN-31 Early 4H4-C mod NC-300, HRO-60 MAR 8, 1956
FSN-33.1 Certain NC-300s NC-300 JAN 26, 1956
FSN-33.2 Notes NC-300 JAN 26, 1956
FSN-33.3 Notes NC-300 JAN 26, 1956
FSN-33.4 Notes NC-300 JAN 26, 1956
FSN-34 IMD Reduction in NC-300 NC-300 JAN 26, 1956
FSN-35 NC-300 S-Meter Sensitivity NC-300 FEB 17, 1956
FSN-36 Reduc.Spurious Response/BCI NC-300 MAR 28, 1956
FSN-37 Final Notes on NC-300 NC-300 APR 16, 1956
FSN-38 Reverse TVI (ITV) filter NC-300 JUL 25, 1956
FSN-39 WWV Reception w/ NC-300 NC-300 JUL 30, 1956
FSN-41 Final 4H4-C > 6V6 FSN NC-300, HRO-60 NOV 23, 1956
FSN-42 Drift Reduction in NC-183D NC-183D JAN 10, 1957

 Special THANKS!!! to Garey, K4OAH for scanning the majority of these FSNs. 

The NC300 PDF's referenced below are mostly from 73 Magazine and CQ Magazine via Mike, ZF1MW and Don, W4BWS.








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plus... a listing of my Receivers with their own webpages:







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