Reversed Electrolytics redux

[Dave G4UGM]

> 
> Also, I now know why the +5 V is high.  It has a UA 7805 3 terminal
regulator
> serving as a voltage reference for a TIP-3055 so the supply can provide
more
> current.  That 7805 has a forward biased diode between the center terminal
> and ground, thus raising the output voltage by right around 0.5v.  I
expect I
> will leave it alone.


When used as series pass transistor the TIP-3055 will usually drop 0.6v
across the emitter under any significant load. Adding a silicon diode in the
7805 base is the normal fix...

http://www.bristolwatch.com/ele/basic_power_supplies.htm

> 
> The same design is used for the +24V, which comes out at 24.2V.
> 
> So, odds are that this supply could drive two floppy drives.
> 
> JRJ
> 
> 
> JRJ