On Thu, 25 Jan 2018 14:36:54 -0600
wrote:
In article
-september
..org, (Recliner) wrote:
By your logic, TfL should have ordered more of the proven, in-service
313s, not the dangerously new-fangled 378s, when increasing the LO fleet.

In fact, with modern manufacturing, especially where electronics are
involved, technology can move on to the point where obsolete design
manufacture is no longer affordable because the machinery is no longer
available.

This happened in the late 1990s with the radios used for RETB signalling.
Railtrack wanted more of an obsolete design of the radios which used a form
of electronics which was no longer makeable, more or less at any price. This

That sounds highly unlikely. You can still buy chips designed in the 70s
if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

so the chances of whatever microcontroller the radios used being unavailable
is pretty slim. Plus the analogue radio components and op-amps will always be
available until someone invents usable optotronics. More than likely the cost
of redesigning the board for SMDs was more than railtrack was prepared to pay.