Obsolete TransZorb — what the ratings mean for a replacement search
The 1.5KE250-E3/73: The 202V reverse standoff voltage means it starts conducting above a 202V DC rail — sized for 200V nominal bus protection where the clamp triggers before the downstream silicon sees 360V. Vishay lists this part as Obsolete.
Package and rework angle — DO-201AA axial
Through-hole DO-201AA (DO-27) axial package — the body is large enough to hand-solder or rework with standard iron and solder wick. The banded cathode end is the only orientation mark; on a crowded board the band can be hard to read after wave solder, so a silkscreen outline on the PCB helps avoid a reverse-insertion mistake.
Because the 1.5KE250-/73 is obsolete, new-stock supply runs through independent surplus channels.