IBM transistor replacements

Al alsilisk at
Sat Nov 27 15:10:03 CST 2021


Thank you, I will see if I can find a modern day equivalent of that and compare them, always useful to have spares on hand. 



(Also, apologies for the hideous formatting on my last email, something got very broken somewhere) 

> On 27 Nov 2021, at 21:00, Gregory Beat via cctalk <cctalk at> wrote:
> 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)
> greg
> ==
> 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, 
> Al

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