Ever seen one of these ?
Now I know everybody has seen the version that plugs into 110 and uses a neon light to indicate heater continuity , but this is the first battery powered one I've ever seen . Talk about handy for finding open heater tubes* it's about the size of a pack of cigarettes and doesn't need AC power .
*Yes I do realize that these simple heater checkers only work with the most common heater base pinout tubes (2 & 7 for Octals , 3 & 4 for 7 pin , and so on) and not all tube's heaters can be accurately checked with it . Here you see it indicating heater continuity on a 6AL5 .
Last edited by init4fun; 02-18-2018 at 02:26 PM.