[time-nuts] Defective Z3801 and strange PS board

[Jim Lux]

On 7/9/11 8:31 AM, Bob Camp wrote:
> Hi
>
> Guess 1:
>
> Design it all with the first set of switchers, run it through all the fancy do them one time tests. Get to the last test, fail. Project is now well behind schedule.
> What's the fast fix? Slap on a wider range / lower emission / better isolation / what ever switcher in front of what you have already. Not pretty, but much faster than doing it right.
>
> Guess 2:
>
> Inventory items reduction fun and games / use the standard parts list. Much easier to design with parts that somebody else has put into the system than to put in new ones. Might even get a gold star for doing it that way. Companies get on those sort of band wagons from time to time.
>



not to mention that power efficiency probably isn't a design criteria 
for this kind of gear.  Nobody is going to make a comparison chart 
between this and a similar product from a competitor and say...  Well... 
that HP unit consumes a watt more, but has -150dBc/Hz noise and the 
other box has -145 dBc/Hz.

I think we should buy the lower power box.


Multiple power converters in series is a very, very common scheme.  It 
lets you do a lot of the regulatory compliance stuff (power factor, 
conducted emissions, conducted susceptibility) in just one place, too. 
You do a qual run for your series of first line converters, and then you 
can do whatever you like for all the downstream converters.