12AL5
The 12AL5 (European type HAA91) is a dual diode vacuum tube with a miniature 7-pin base.
It is used as the "disconnect diode" in the timebase circuit of several tube-era Tektronix scopes.
Heater: 12.6 V, 0.15 A
System: max. 420 V peak, max. 9 mA, 2.5 pF