Testing Power Supplies! Re: Norsk Data Nord-10/S restoration

[Tony Duell]

> 
> Paul Koning wrote:
> 
> >  Tore> But access to a complete array of spares if nessecary. Oh, and
> >  Tore> the CPU is built in TTL logic, so no hard-to-get spares.
> > 
> > TTL is getting hard to find, especially the more obscure types such as
> > 74S series.  (And if the book says they want 74S, it's quite possible
> > no other variant will work...)
> > 
> >    paul
> 
> I thought that 74F series parts were generally replacements for 74S
> parts.  Is this incorrect?  A more serious concern is that the parts

'Generally' is right. 9 times out of 10 you can use 74F in place of 74S 
(if the right function exists, which is by no means certain). The tenth 
time, the F part is too fast, or causes too much ground bounce, or ...

-tony