27 Nov
2021
27 Nov
'21
11:22 a.m.
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 icloud.com>
To: cctalk at classiccmp.org
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:
https://drive.google.com/drive/folders/1JTnsWS4A8NrYJNFsqK2ejOeqqJNjoF1w?us…
Thanks in advance,
Al
27 Nov
27 Nov
1:10 p.m.
Greg,
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.
Thanks,
Al
(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 classiccmp.org> 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 icloud.com>
To: cctalk at classiccmp.org
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:
https://drive.google.com/drive/folders/1JTnsWS4A8NrYJNFsqK2ejOeqqJNjoF1w?us…
Thanks in advance,
Al
2:53 p.m.
On 2021-Nov-27, at 11:22 AM, Gregory Beat via cctalk wrote:
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 the JEDEC number, 2N139 would be a 50s-era
transistor, way earlier than the ones at issue.
2N139 specs are Ge-PNP, 16V/12V CE
max, 15mA IC max, 35mW max, which can find a use in transistor radios, but highly unlikely
to be what the OP is looking for.
3:09 p.m.
139 is a "nickname" number. IBM used these nicknames for some reason,
instead of the full IBM part number.
A 139 is really an IBM part number 2414938, a silicon device in a TO-18.
Gee, it would be great if this list could take pictures so I could
just post one with all the specs...
--
Will
On Sat, Nov 27, 2021 at 5:54 PM Brent Hilpert via cctalk
<cctalk at classiccmp.org> wrote:
On 2021-Nov-27, at 11:22 AM, Gregory Beat via cctalk wrote:
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 the JEDEC number, 2N139 would be a 50s-era transistor, way earlier than the ones at
issue.
2N139 specs are Ge-PNP, 16V/12V CE max, 15mA IC max, 35mW max, which can find a use in
transistor radios, but highly unlikely to be what the OP is looking for.
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