EICO TUBE TESTER 625

I just finished repairing the tube tester. It ran me ragged. It would only test half of a 12au7 and other dual element tubes. The tester wouldn't test some single element tubes also. I made sure the tubes were good in my Hickok 800. Thru all this I learned a lot about tubes and the wiring of the sockets for testing tubes. All this said and done I made a comparison of tubes 9 pin and octal. Decided the tester was probably home built kit. That is when I started checking the wiring from socket to socket. Found out that the octal tube socket had been miss wired at the fourth and fifth pin. I moved the wire and then the tester came to life. Hard to tell how long it had been wired wrong.

That's good to see! Persistence pays.