Does anyone have a HP Transistor cross reference?? I am repairing a HP6209B power supply and the Main Pass Regulator transistor is a HP house number 1854-0225 and wondering what part it really is?? its TO-3 NPN transistor.
Zc
Zc
There are lists of HP to JEDEC part number equivalences but none list 1854-0225. The eevblog forum has a discussion that may be helpful.
https://eevblog.com/forum/repair/how-do-you-replace-a-power-transistor-that-is-no-longer-available/
Post #10 says:
HP part # 1854-0225 (Transistor NPN VCE-60V IC-15A PD-115W FT-0.5MHz Silicon TO-3) was superceded by part # 1854-1017, which I think was an epitaxial 2N3055 selected for lower gain (~15) & higher SOAR to match the original selected homotaxial RCA 2N3055.
Something like a 2N3771/2 is the usually recommended substitute though, as bd139 mentioned, you'll probably have to make minor mods to ensure stability with the higher Ft of modern parts.
https://eevblog.com/forum/repair/how-do-you-replace-a-power-transistor-that-is-no-longer-available/
Post #10 says:
HP part # 1854-0225 (Transistor NPN VCE-60V IC-15A PD-115W FT-0.5MHz Silicon TO-3) was superceded by part # 1854-1017, which I think was an epitaxial 2N3055 selected for lower gain (~15) & higher SOAR to match the original selected homotaxial RCA 2N3055.
Something like a 2N3771/2 is the usually recommended substitute though, as bd139 mentioned, you'll probably have to make minor mods to ensure stability with the higher Ft of modern parts.