Epson PF10 problems

[Tony Duell]

> 
> > You can turn it off with the little switch inside the main batter
> > compartment. The machine should run from the main battery
> > (or a 5V PSU connected in place of the main battey) if there
> > are no otehr problems.
> 
> Both of my PX-8s (an earlier and a later model) will run with the 6V
> wall wart connected into the proper socket when the main and wedge
> batteries are removed.  I wouldn't exactly recommend bypassing the
> little bit of protection the charger input provides.

I would strongly recomend against doing that. There is no real regulation 
in the input circuit of the PX8, it depends on the battery to clamp the 
supply voltage. Yes, there is a protection zener (D19 iIRC, I had to 
replace it on my machine, it was litereally blown off the board), but 
it's something lik 7.5V so it doesn't offer much protection.

Running the machine from a _regulated_ 4.8V or 5V supply in place of the 
battery is safe. The logic gets that voltage (less a little bit dropped 
across the switching transistor), much the same as it would get if there 
was a NiCd installed.

-tony