BillJ wrote:
I have Sylvania Electric tube tester. Has worked for many years, but
today known good tube test flat zero. Filaments do light. I have no
model number, it is a green panel, with roll chart.

Anybody know what might go wrong. I looked inside and see one tube, a
1EL7 I think it was. Other wise looks good, with no bad smells.

Thanks, Bill

Don't assume that a known good tube is still good. Test your tester
on more than one tube. If you are really lucky that will be the
problem.

Irv VE6BP