This article will discuss servicing of the Lafayette TE-50 tube tester. Electrical voltages are present, repairs should only be attempted by a qualified technician. Copyrighted, all rights reserved. Ebay ID = rjputnak

The Lafayette TE-50 is an excellent example of a nice portable tube tester that packs a lot of punch into a very small package. Measuring only 10 x 9 x 4 inches and weighing approx 6-lbs, you have a tube tester that can be easily taken on the road, while at home, it only occupies a small bench area. The instruction manual, tube charts, and substitute chart are attached to a drawer that tucks away neatly inside the tester. (The drawer handle is NOT a carry handle!) The all-metal chassis is very durable. A black fabric carry case with handles was also supplied.

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Redone from scratch, a new product from us at TubeSound. A new manual package for the Hickok 530, 530B, and 510X tube testers. Includes schematics and ballast setup chart. The product covers all three models (530/530B/510X).

Benefits include: all instructional text being newly transcribed into computer by hand; factory text errors & grammatical errors corrected; factory addendums integrated into the text; and page layouts enhanced for much improved readability. The readability and presentation of this product is “Light Years” better than the original document!

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This article provides examples of NATIONAL UNION-manufactured tubes.

NATIONAL UNION was another quality USA tube manufacturer with most production dating from 1930s to 1950s. Their production numbers were significantly smaller than the big name brands (RCA, Sylvania, GE).

The NATIONAL UNION (EIA) code number is “247″. Here is an example:

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This post provides examples of Raytheon manufactured tubes.

Raytheon was an extremely high quality USA tube manufacturer with prolific output, covering both civilian issue and a vast majority of US Military parts production. The Raytheon (EIA) code number is “280″.

Here is an example:

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It is quite common to find tubes that have a “brand name” printed on them, but were actually manufactured by a different company. Yes, you can easily find “RCA” tubes made in a Sylvania factory, “GE” or “RCA” tubes manufactured in a Tung-Sol plant, etc.

So how do you know which company actually manufactured your tube? Most tubes have a Factory Code on them, an EIA code (Electronic Industries Association), and that code tells you the answer.

Here are the most common factory code numbers found on tubes:

• 111 = Amperex
• 158, 171 = DuMont
• 188 = GE / KEN-RAD (188-4, 188-5, 188-20, etc.) [info]
• 210 = CBS Hytron [info]
• 247 = National Union [info]
• 274 = RCA [info]
• 280 = Raytheon [info]
• 312 = Sylvania [info]
• 322 = Tung-Sol (USA)
• 323 = United Electronics
• 336 = Western Electric
• 337 = Westinghouse
• 722 = Sylvania-manufactured for OEM equipment makers (Allen Organ…)
• 1022 = Fisher branded Mullard/Telefunken/Amperex
• 1109 = Raytheon (Japan)
• U.S.A.3 (found on the glass envelope) = Tung-Sol
• Xf1,Xf2,Xf3,Xf4 = Mullard
• 7C,8I = Toshiba (Tokyo Shibaura Electric)

Examples:

(1) you have an “Admiral” tube with “188-5″ codes. GE made your tube.

(2) You have an RCA 5881 with “U.S.A.3″ code on the glass. Tung-Sol made your tube.

There are many other “clues” also. For example, many Sylvania 12AX7A tubes have the tube designation printed in white-gray letters, vertically stacking all three designations of “12AX7A ECC83 7025″  Only the Sylvania factory used this exact marking.

It just looks like an RCA...

Sylvania markings.

distinctive markings of the Sylvania 12AX7A

Example: Stacked printed designation “12AX7A ECC83 7025″.

Here is an example of unique Sylvania-manufactured designation for 12AX7A tubes, where the tube is printed as “12AX7A ECC83 7025″ vertically stacked. In this example, this tube is branded as an RCA, but was in fact manufactured by Sylvania. Compare to the Sylvania-labeled tube.



When I have more time, I will continue to add more clues here to help you determine who manufactured a tube when it does not have a factory code number.