[R-390] obsolete transistor list

[Jim Whartenby]

I'm not sure what you are looking for.  Do you just want lists of transistor part numbers, device data, or substitutes?
A 1960 era Lafayette Transistor catalog is available here:
https://worldradiohistory.com/Archive-Catalogs/Lafayette-Catalogs/Lafayette-Radio-BK-1300-1960.pdf
A pdf of the D.A.T.A Book of Discontinued Transistors, 5th Edition, Summer 1969 (12.4 megabytes !) is available here:
https://ia600304.us.archive.org/13/items/DATABookOfDiscontinuedTransistors19695thEdition/DATA%20Book%20of%20Discontinued%20Transistors%201969%205th%20Edition.pdf

AFAIK, Germanium transistors have much higher leakage current and this leakage current becomes part of the bias circuitry.  Silicon has orders of magnitude less leakage so voltage divider bias and collector to base bias techniques are used to properly bias the transistor.  For any device, as long as breakdown voltage, current, power rating and upper frequency limit of the substitute exceed that of the original device, the circuit should work.
I work on the Cold War era KWT-6 which was developed as silicon transistors first went into volume production in the late 1950's.  This transceiver uses just about an equal number of 7 & 9 pin button based and wire leaded subminiature vacuum tubes along with just about equal numbers of  Germanium and silicon transistors.  It is an interesting radio.  
Germanium transistors used in the Reference Oscillator module during the KWT-6 productionlife include 2N128, 2N499, 2N1753 and 2N3325.  These later transistors were used with no required changes to the Reference Oscillator circuitry.  The main problem with the RO is that the earlier Germanium transistors are failing as the un-passivated transistors give up the ghost to metal migration due to the interaction of aluminum bond wires with the semiconductor substrate, or so I have been told.
Eventually, someone will have to figure out what needs to be done to the RO so that silicon PNP transistors can be used to replace the failing PNP Germanium transistors.  This is assuming that leaded silicon transistors don't also go the way of the dinosaur!
Regards,Jim


Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy

-----Original Message-----
From: David C Hallam <collinsuser at outlook.com>
To: Jay Simmons <jaysimmons at chasingrainbows.com>; r-390 at mailman.qth.net
Sent: Mon, Jul 25, 2022 9:56 am
Subject: Re: [R-390] obsolete transistor list

Jay,  Did you ever get this list?  If so, I would like to get a copy.

David
KW4DH

On 7/20/2022 9:24 PM, Jay Simmons wrote:
>
>
>            Would whom ever posted the web site for the Obsolete 
> Transistors, please re post it to the List.    Thank you so much...Jay 
> Simmons  K6RIY
>
>
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