Hi Ron,
   Old transistors can go bad due to corrosion and such.  If the junctions still show diode voltage drops and the transistors still test ok and show Beta or hfe, then they are likely alright.  The Beta/hfe values should meet minimum published transistor specifications.  You could try matching a pair by similar Beta and/or junction forward voltage drops. 
   Nice project.
73
Ed, KI6R

On Wed, Oct 22, 2025 at 11:38 AM <rl.boltz@mhsdesign.com> wrote:

Do NOS germanium transistors get “rot” or go bad from age?  I need to replace the invertors in a PRC-47 and I have 5 NOS original germanium transistors.  All test vastly different. I expect variations as not matched sets but these are WAY off.  I suspect at least 60 years old and maybe much more.

 

Ron Boltz

K3tzj

 

 

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