GE Medical cancelled the contract years after Eimac fixed the heat dam
problem.
>Rich made an incorrect statement that ETO was to blame for 8877 failures.
>
>The 8877 failures with GE medical were well known to be a manufacturing
>problem with the tubes. Eimac fought that problem for a long time before
>they had any useful tubes. For a long period of time virtually every tube
>was defective, none of the manufacturers using 8877 tubes could get a tube
>that lasted.
>
>8877's continue to be one of the more difficult tubes to produce. Although
>the move back to the San Carlos plant made them much better they still are
>less reliable than other tube types.
>
>I explain why at:
>
>http://www.w8ji.com/vacuum_tubes_and_vaccum_tube_failures.htm
>
>This is similar to the 572B Svetlana fiasco Ameritron (who I no longer do
>any consulting for) went through, and seems to parallel the present 3-500Z
>problem.
>
>As difficult as it is for some to believe, transmitting power tubes are very
>troublesome components. They are very much material sensitive, and
>manufacturing process sensitive. It is almost like a black art, as anyone
>who has been around tube manufacturing would know. Even small receiving
>tubes operating in low-voltage systems were the most likely components to
>fail in old tube equipment.
>
>We seem to have forgotten all the lessons we have learned, and expect
>solid-state reliability from vacuum tubes.
>
>73 Tom
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
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