S-100 power supply voltage ranges

[John Robertson]

Andrew Lynch wrote:
> Hi!  What are acceptable voltage supply ranges for an S-100 power supply?  I
> am assuming 115VAC input.  My intended application is a small home brew
> S-100 backplane.
>
> I have seen the S-100 voltage rails vary but I believe +15VDC, -15VDC, and
> +9VDC would be sufficient.  Herb's S-100 page lists the voltages as +18VDC,
> -16VDC, and +8VDC but I have seen other voltages used.
>
> Thanks and have a nice day!
>
> Andrew Lynch
>
>
>
>   
While I do not know all the ranges of voltages folks here are dealing 
with on many classic computers I can assure everyone that putting in 
devices called "Tranzorbs/Transorbs" for machines running with Linear 
Power Supplies (not as required for switching supplies) may protect your 
computer from problems with linear power supplies that do not have 
output voltage protection.

In the old days the manufacturers often used devices called "Crowbars" 
that would literally short out the outputs of the supply if the output 
voltage rose past a predefined point. This would protect the downstream 
components from most power supply issues.

Lots of folks here are in areas with less than perfectly regulated mains 
and Transorbs can also smooth down momentary surges.

Transorbs can be found with many suppliers and they can easily be added 
to most power supplies - if you are concerned that the Transorb will 
burn out (perhaps those 100A 5VDC rails) then you can put a few in and a 
fuse between the supply and the Transorb (and load). The fuse should 
blow before the Transorb explodes...

MOVs on the line input can protect your devices from lightning strikes, 
etc. and are contained in good quality surge suppression protection 
extension cords or UPS supplies.

John :-#)#

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