Eico

Eico 667 Schematic Here is the schematic from the Eico 667 tube tester. It is very similar to the 666,

The Eico Tube Tester Range Among the many popular tube tester brands to find at swap meets, Eico has to

Eico 666 / 667 Tube Tester First seen about 1956, this Eico ‘Dynamic Conductance’ tester is a very popular model to find