In some ways transistors are easier the replace than tubes. Most only have 3 leads.

ECG cross reference for 121-687 is #316. Most electronic stores will know this number. It's listed as a high frequency, silicon, NPN transistor.

Norm

:tubes I can find....
:
:BUT what about the pesty Z7000 series transistors
:part number 121-687
:
:I could use 3...
:
:who stocks and sells those? and the others?
:
:Nick
:Plano, TX
: