IBM transistor replacements

Gregory Beat w9gb at
Sat Nov 27 13:22:33 CST 2021

Al -

The Texas Instruments (TI) 139 is likely a 2N139 PNP (BJT) transistor, 
capable of high speed switching (in that era).

The 2N139 was originally an RCA transistor (tall cylinder) found in RCA and GE transistor radios (455 kHz IF section).
The TI versions were low profile metal case, TO-33 case (8.5 to 9.5mm diameter)

From: Al <alsilisk at>
To: cctalk at
Subject: IBM transistor replacements

Dear all, 

A while ago I received an IBM 3286 printer, annoyingly some of the transistors in the printer section have been corroded. 
What I am having trouble with is reading the part codes and finding a modern equivalent of them. 

One has a Ti logo and two sets of numbers (attached). Does anybody know which numbers are the part numbers and if they are IBM house numbered? 

Photos of the Ti transistors and card assembly:

Thanks in advance, 

More information about the cctech mailing list