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References: <BLU146-W201F9B3FE3E982D483D89BCFA30@phx.gbl>
Date: Fri, 23 Jul 2010 22:05:15 +0100
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From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: Noise R75 - rs232 from smpsu -
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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.


Andy
www.g4jnt.com


On 23 July 2010 21:47, Laurence KL7UK <hellozerohellozero@hotmail.com>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
>
> ------------------------------
> The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with
> Hotmail. Get busy.<http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_5>
>

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<div>Yes, I&#39;ve played with running laptops including Dells from all so=
rts of power supplies.=A0=A0The nominal voltage can go a goodly 10 - 20%=
 either way before it flags an error=A0- and they seem to detect over volt=
age and take evasive action, although couldn&#39;t guarantee all do.</div>

<div>=A0</div>
<div>BUT there&#39;s a big snag with Dells.=A0 If youv&#39;e got one with=
 the three way coaxial DC connector (it has a very thin centre pin) - the=
 PSU contains a DS2502=A0 one-wire EEPROM..=A0=A0 The Laptop interrogates=
 the PSU to find out if its satisfactory and if the EEPROM isn&#39;t prese=
nt, the laptop will use the external power, but refuse to charge the batte=
ry.=A0=A0=A0 On a 12V input mobile PSU=A0I had to butcher a surplus=A0Dell=
 black brick=A0to get the EEPROM and incorporate it into the connector for=
 the new PSU.</div>

<div>=A0</div>
<div>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.</div>
<div>=A0</div>
<div><br clear=3D"all">Andy<br><a href=3D"http://www.g4jnt.com">www.g4jnt.=
com</a><br><br><br></div>
<div class=3D"gmail_quote">On 23 July 2010 21:47, Laurence KL7UK <span dir=
=3D"ltr">&lt;<a href=3D"mailto:hellozerohellozero@hotmail.com">hellozerohe=
llozero@hotmail.com</a>&gt;</span> wrote:<br>
<blockquote style=3D"BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8e=
x; PADDING-LEFT: 1ex" class=3D"gmail_quote">
<div>=A0<br>Anyone done any common mode noise mitigation from the RS232 po=
rt of the R75 Rx&gt; - the noise coming up from the SMPSU/processor from=
 the old Dell puter=A0- 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 - <br>
=A0<br>Anyone had any success of powering a Dell D series from a non stand=
ard 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...)<=
br>
=A0<br>with thanks<br><font color=3D"#888888">=A0<br>Laurence Kl7UK<br></f=
ont>
<div class=3D"hm"><br>
<hr>
The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with=
 Hotmail. <a href=3D"http://www.windowslive.com/campaign/thenewbusy?tile=
=3Dmulticalendar&amp;ocid=3DPID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_=
5" target=3D"_blank">Get busy.</a></div>
</div></blockquote></div><br>

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