The 152-0489-00 is a 21 mA, 1.5 pF tunnel diode made by
It is used in the 1502 and 3T7.
In the 1502, it is CR1703 and the description in the parts list is "SMTD0892 w/ clamp".
152-0489-00 as CR587 in 3T7 pulser
152-0489-00 as CR1703 in 1502 pulse generator