On Thu, 09 Dec 2004 12:50:25 -0500, Jack Erbes
wrote:

Rodney Myrvaagnes wrote:

The laptops I have used on boats--NEC, HP, IBM, and Toshiba-- all had
cigar lighter cords with no transformer. I suspect all that was inside
the bulge was overvoltage protection.


Are you sure about that? I have run Toshibas, Compaqs, and Thinkpads
from with both OEM and after market "auto" adapters. All of those had
to increase the voltage above the nominal 12 volts.

The good ones produced a steady and stable higher output voltage while
on the cheaper ones the output went up and down with the input but
stayed above it.

Some newer laptops have pretty robust DC-DC inverters and may run off of
anything that is close to right. But I'm too thrifty to test that
theory though because I have had some laptops that quickly fried DC-DC
inverters on ripply DC or under/over voltages.

Jack
No, I didn't take them apart. I was guessing by the size of the bulge
in the cord.


The most recent of these machines is a 1995 Toshiba Libretto, the
THinkpad was a 701 "Butterfly" from ca 1989, the HP was a 386SX
machine, which must be ca 87, and the NEC was 84.

THe NEC I know didn't step up. It was just a cord. THe HP had its PS
internal. It used a conventional PC power cord and couldn't be used
with a lighter socket except with an inverter.

I doubt anyone is trying to use any of these on a boat now. The
Libretto still works fine, but places I could previously plug in a
modem now need Ethernet or wifi to call out, so it retires from boat
duty before spring.





Rodney Myrvaagnes NYC

Let's Put the XXX back in Xmas