Yes, I've played with running laptops including Dells from all sorts of
power supplies. The nominal voltage can go a goodly 10 - 20% either
way before it flags an error - and they seem to detect over voltage and
take evasive action, although couldn't guarantee all do.
BUT there's a big snag with Dells. If youv'e got one with the three
way coaxial DC connector (it has a very thin centre pin) - the PSU contains a
DS2502 one-wire EEPROM.. The Laptop interrogates the PSU to
find out if its satisfactory and if the EEPROM isn't present, the laptop will
use the external power, but refuse to charge the battery. On
a 12V input mobile PSU I had to butcher a surplus Dell black
brick to get the EEPROM and incorporate it into the connector for the new
PSU.
Those EEPROMS are supposed to be easy enough to read, so when I need one
again, will read the contents and stick them into a fresh chip.
On 23 July 2010 21:47, Laurence KL7UK
<[email protected]>
wrote:
Anyone done any common mode noise mitigation from the RS232 port of
the R75 Rx> - the noise coming up from the SMPSU/processor from the old
Dell puter - cable is double screened - choking off using J (75) type
has seen little improvement - this is my last hurdle to unimpeded remote rx
on 137 - any pointers appreciated - everythings bonded and Ive tried the
on/off earth tricks at various locations -
Anyone had any
success of powering a Dell D series from a non standard non switched PSU?
(the noise goes away when the DC from the Black Dell brick is removed but it
may also be partially screen/processor noise...)
with
thanks
Laurence Kl7UK
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