[CW] Need manual for a Curtis Electro Devices Model 420 keyer

[Sherrill E. Watkins]

Gentlemen: I really need a manual for a recently acquired Curtis Model 420
keyer. I have inquired everywhere and none of the usual sources can supply
this exact model. Someone had a manual for a 420A but could not tell me what
the difference is? There was a review in the Oct. 1973 issue of QST but the
information supplied is of little use. Thank's in advance to anyone who can
help me! - Sherrill E. Watkins  K4OWN