Serial No.77960 F108
RCA Transistor Tester model WT-501A. Designed to measure Hfe from 1 to 1000 at collector currents from 100 micro Amps to one Amp in four ranges. It has the capability of measuring transistor performance in circuit and measuring leakage currents. Requires two 1.5volt type D cells. Working, USA, date 1968/9.
This is one of several instruments given to me by Deborah Waters, which belonged to her late father.
Interior of the instrument [note that the leads to the cells have to be soldered]
There are brief instructions on the back of the plastic case.