[Milsurplus] How Much Vacuum in "Vacuum Tubes?"

[Jim Klotz]

Jim, all

My dad used to work in the Sylvania Electric Products warehouse in Seattle. 
When I was a teenager (early 1960's) I worked with my dad in the summers. 
Two of the interesting things I did there were: 1. To let air into returned 
TV picture tubes in preparation for shipping.  There was a special wrench 
used the break off the center locating pin of the tube plug which revealed 
the glass seal.  Tapping the seal cracked it and you could hear the air go 
in.  Those tubes were shipped off to be refurbished but I don't know where. 
It was also interesting to me that the picture tube boxes had a "heavy 
corner which was always turned into the middle of a stack of boxes on a 
pallet.  made the stacks quite stable.  And 2. paste various other brand 
labels on Sylvania picture tubes and their boxes.  I remember specifically 
putting Sears and Zenith labels on.  I don't know if this is true, but I was 
told at the time that each CRT manufacturing company made certain types of 
tubes and these were rebranded for other companies when they used a tube of 
a type they didn't make in one of their products.

Cheers,
- Jim Klotz

----- Original Message ----- 
From: "J Forster" <jfor at quik.com>
To: <milsurplus at mailman.qth.net>
Sent: Wednesday, March 28, 2007 4:59 PM
Subject: RE: [Milsurplus] How Much Vacuum in "Vacuum Tubes?"


> I can remember the old ads in Popular Electronics, Mechanix
> illustrated,
> etc. where you could go into business rebuilding old TV CRTs.  Probably
> a
> scam, I never knew anyone who responded to the ad and see what you
> would
> get.
>
> 73, Jim, wd4air
>
>
> Actually, rebuilding a picture tube would be easier than a receiving
> tube, IMO. I think you basically cut off the neck and installed a new
> gun and evacuated and sealed the tube. Most of the envelope and screen,
> the big and expensive parts, could be reused pretty easily. B&W picture
> tubes with magnetic deflection all have pretty simple guns
>
> -John
>
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