The Signal Tracers I own are old and large.As large as some table model
radios or larger.I bought them at a thrift store years ago and I also
own some radio and tv tube testers.About twenty years ago,I read
somewhere that most of those tube testers such as the kind we used to
see in the stores,food stores,drug stores,hardware stores and the
like,are not accurate so as to fool people into buying some new tubes.
cuhulin