Motran transistor replacements

k2hz · Post by **k2hz** » Wed Mar 22, 2006 8:00 am

I am attempting to find any available substitutes for the switching transistors used in the RR Motran power suppy:

M9423 / 48-869423
M9437 / 48-869437

I can't find any data or cross reference on these transistors.

AEC · Post by **AEC** » Wed Mar 22, 2006 10:23 pm

What are the case styles...TO-220, TO-5...Etc...?

That also helps to locate the devices if one does not have the manual in hand.

k2hz · Post by **k2hz** » Thu Mar 23, 2006 5:46 am

They are TO-3 PNP. The 9423 is used in the 64V converter and the 9437 in the 12V converter. The fact that there is no ECG/NTE replacement listed for these makes me wonder what is unique about them.

The 9436 audio output transistors are replaced by NTE121. It is only these 2 types of that TO-3 PNP M94xx series that don't seem to have any listed equivalent. I have a source with a few originals still available but I am wondering if there is a generic replacement.

Will · Post by **Will** » Fri Mar 24, 2006 5:07 pm

If I remember that far back, the switching transistors are Germinium PNP's. They may be common on the Motrac LHT, MHT series radios.

I think I may even have one Low Band left in the storrage.