my cw 80 works fine for my postwar whistle tenders, but when i hook up to my kw or zw transformer the tenders sound like they are coughing and hacking.The KW
and ZW transformer i bought from 2 different transformer restoration guys at the TCA york fair around 3 years ago ...does anybody have information on testing the whitsle switch with a multimeter... both transformers have diodes in them