S-100 power supply voltage ranges

[Jim Battle]

Chuck Guzis wrote:
> All of the S100 boards I've seen use simple linear regulators, so you 
> 
> need some headroom--but not too much.  A lot of S100 7805s and LM323-
> 5s were operated within an inch of their maximum current ratings 
> (some had bypass resistors installed) and generated a lot of heat.  I 
> 
> wouldn't run the supply rails any higher than I had to.
> 
> Cheers,
> Chuck
> 
> 

The Sol-20 had an app note about this problem.  Apparently they shipped 
them for a while with transformers that were out of spec with the end 
result that the unregulated power ran high.  The recommended fix was to 
take a power bridge, mount it to the case, and wire it in series with 
the positive voltage run in order to get a ~1.4V drop.