Date: Wed Apr 18 13:16:00 2007

Author: J. Terrence Klopcic

Subject: More on the Rebuild Idea

As previously pointed out, the idea of getting the old Sargent-Welch tubes
rebuilt has surfaced before. I found the attached in my files.

Peter, are you still on-line? If so, anything ever come of your inquiries
at Kennetron? Did you suggest to Kennetron that they might have dozens of
customers, and several dozen rebuild jobs to get their money out of any
up-front set-up time they need to invest?


----- Original Message -----
From: "Nelson, Peter"
Sent: Monday, August 07, 2006 3:42 PM
Subject: Re: [tap-l] Need obsoleted Welch Requests

> Mary:
> I too am interested in purchasing this same replacement electron
> diffraction tube (model 2639). I have many pictures and the manual
> available if you need them.
> In my efforts to get ours fixed, I have spoken to a company called
> Kennetron, who rebuilds all sorts of vaccuum tubes, on several occasions
> about repairing ours. They always seem interested in making the repairs
> but never reply to my requests for an estimated repair cost. I am
> reluctant to risk sending it off to them, at least not while there is a
> little life left in the tube. Has anyone else heard of this company,
> or made contact with them?
> - - - - - - - - - - - - - - - - - -
> Peter Nelson
> K-State Physics
> Manhattan, KS 66506
> -----Original Message-----
> From: [] On
> Behalf Of Torres-Isea, Ramon
> Sent: Monday, August 07, 2006 10:03 AM
> To:
> Subject: Re: [tap-l] Need obsoleted Welch Requests
> Hello Mary,
> I would be interested in purchasing three Electron Diffraction tubes
> (Model No. 2639...information obtained from descriptive literature
> pamphlet No. 452.21A, Copyright 1963, Welch Scientific).
> Here is the description that you asked for:
> Tube is 50 cm long with an electron gun at one end and a 16-cm-diameter
> fluorescent flat screen at the other. A 2x2-cm etched mesh target is
> supported about halfway between gun and screen. Electron beam can be
> accelerated up to 10 KV and directed to probe any area of the target.
> Tube also includes connections to externally control focusing and beam
> deflection. Graphite and Aluminum targets are incorporated in the mesh.
> The tube was made by General Electric, type: Z4904P4.
> Thanks for pursuing this.
> Ramon Torres-Isea
> Adjunct Lecturer and Supervisor,
> Advanced Physics Teaching Laboratories,
> The University of Michigan, Ann Arbor, MI.
> -----Original Message-----
> From: [] On
> Behalf Of Mary Creason
> Sent: Monday, July 31, 2006 11:36 AM
> To:
> Subject: [tap-l] Need obsoleted Welch Requests
> While chasing down the Electron Diffraction Tube issue (obsoleted and
> looking for a new supplier)
> A request from CENCO Physics Technical Help for your obosoleted
> Welch/Sergent-Welch/CENCO apparatus that you would like them to have
> upgrade suggestions, reworks, resurrections, etc. Please give a model
> number and a brief description.
> Reply to this thread and I'll send them the list.
> Mary