On 2 Jun 2020 at 17:07, Kenneth G. Gordon wrote: > I also have a Type 739 tester (Hickock?) which uses a selenium rectifier which has gone > bad and needs replacement, but I have not yet figured out how to do that. Ooops. Mine is a Hickock 539C, not 739... Anyway, I need to replace the selenium rectifier in it... Ken W7EKB