Not sure if l saw your post. Problem is I have no known good tubes to compare to. Dave -----Original Message----- Did you read my previous posting on this thread ? You can test most tubes with only 24V anode voltage and the correct filament voltage. You can perform comparative tests between known good and suspected tubes with this setup. Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist