Were TO-92 voltage regulators difficult to source in the late 1970s?


This 2N4403 is in the regulator hotseat with roughly -22 volts at collector, -16 at base and nothing at emitter. The 2N4401 on the positive rail shows much more reasonable voltages of 13.4, 12.6 and 11.9 respectively.


I'd like to know who drew arrows on this unit, and why. The arrow shown is pointing at the leg on which there should be voltage but is not.


More cryptic hints topside.


I'm tempted to gut the regulator sections and populate with 7812/7912.