Unknown TI logic series

William Donzelli wdonzelli at gmail.com
Sun Dec 19 12:43:47 CST 2010

> It was very common with tubes, too. You can find many German tubes with the
> marking "G.Abl." (=Garantieablösung), meaning that the tube manufacturer
> (e.g. Valvo) would not guarantee anything as they were sold untested (and
> cheaper). They were mainly used by industrial and testing equipment
> manufacturers because they tested these parts anyways.

That was a weird German practice and almost unknown with the big
vendors in the US. Just about the only place you would really see a
big vendor selling logo'd tubes with no guarantee is to the military,
because the whole business model there is wildly different. During the
dark days of World War 2, a few vendors did sell logo'd tubes marked
SUBSTANDARD, but this program was *very* short lived (and pretty
pointless, with the MR (Maintenance and Repair) program already in

The big vendors would sell reject tubes to a 2nd tier of vendors, but
these *never* had any logos or ID marks applied. They tried very hard
to keep their names in no way connected to these "seconds", and were
sold "out of sight, out of mind".

In the US, if an industrial or test equipment manufacturer needed
special testing for a tube, perhaps with tighter or weirder
requirements, most vendors would do it for a price. Sometimes a new
number would be given to a standard tube, or sometimes a discrete code
would be printed on the tube.


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