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Yes ,
Dell batteries also have a
serial number within, fried of mine brought a 'new' battery
while he was working on a big IT project in India , only no serial /
type number .. it worked but after paying full price he took it back
..slight resistance until the shop realised 'he' knew
what he was talking about ..
G ..
Sent: Monday, July 26, 2010 2:30 PM
Subject: Re: LF: Noise R75 - rs232 from smpsu -
I've just ordered a couple of the DS2502 one-wire EEproms contained in
the Dell PSU to tray hacking the contents to make a custom PSU. But
there's a long delivery time on them from Farnell, so that's one project
on hold until October.
Look easy enough to read and write, but they will need a custom PIC
interface as the one-wire protocol is time-slot based. Standard
EEProm programmers can't do the job..
Apparantly, from people who have managed to read the Dell PSU EE
contents, it contains ASCII text giving the voltage and current rating, and the
same serial number as appearing on the label.
One disconcerting finding - every chip has a unique fixed 48 bit serial
number 'lasered' into it at manufacture. So any Dell PSU, (or in
fact any other product that uses these chips as an electronic serial number) can
be uniquely identified - if anyone ever bothered to keep a record.
Don't think it can be read out via the Windoze operating system. Bit
if the part of the Bios that read the PSU data could be identified, its possible
to envision a piece of software that could tell you which PSU was plugged into
it.
Big Brother could be watching you even more closely.
On 26 July 2010 14:10, Dave Pick <[email protected]>
wrote:
Jean-Louis I
had a 12V car/aeroplane adaptor for one of my Dells, made by a company called
LL Power inc. Dell used to sell them as accessories. LL Power have a
web-site at http://www.llpower.comRemember that these
switch-mode adapters will cause RF interference!
Dave G3YXM
From: "[email protected]" <[email protected]>
To: [email protected]
Sent: Monday, 26 July, 2010
8:13:05
Subject: RE: LF:
Noise R75 - rs232 from smpsu -
Dear
all,
Do you
know if there is any 12 V DC power supply supplier for the DELL laptops
?
Jean-Louis
F6AGR
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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