Would all 2BU2s have X-ray filter glass?

[Robert Grant]

Thanks a bunch.

I've got the original tube in there, for now.

If the horizontal foldover is from the old 2BU2, and the new one fixes it, I may switch, since it will be watched very little, and the set operates with HV well below the design maximums.

[Findm-Keepm]

Anybody got a NOS GE 2BU2A? Check the box for the little white patent number label that leads you to the patent GE got for the lead silicate glass they used. No other tube manufacturer licensed the patent, 3854964.

Hence, you had RCA and others making an electrically equivalent tube with less X-ray protection and with a nice disclaimer.

When I worked at Cain Electronics selling both RCA and GE tubes, we quickly figured out why the RCA tubes didn't sell. It took confirmation from the GE folks as to why.

Cheers,

[Findm-Keepm]

A good read, gemane to my above post:

http://tinyurl.com/videokarma

Cheers,

[Robert Grant]

Originally Posted by Findm-Keepm

Anybody got a NOS GE 2BU2A? Check the box for the little white patent number label that leads you to the patent GE got for the lead silicate glass they used. No other tube manufacturer licensed the patent, 3854964.

Hence, you had RCA and others making an electrically equivalent tube with less X-ray protection and with a nice disclaimer.

When I worked at Cain Electronics selling both RCA and GE tubes, we quickly figured out why the RCA tubes didn't sell. It took confirmation from the GE folks as to why.

Cheers,

BINGO!

The replacement tube is branded Sylvania (yellow paint), but was possibly a rebadging of the tube, since there is a separate silvery "2BU2 USA" mark near the bottom.

The original is branded Zenith, but has "188-5" next to the date code. 188-5 is the EIA code for GE Owensboro.