[RFI] Suggestions for linear 19 volt supply?

[John K9UWA]

Last summer in intentionally purchased two monitors that had external wall wart 
supplies. Then I bought a nice 10 amp adjustable Linear supply. Off with the wall 
warts and on with the linear supply. Adjust voltage and done. No noise. 

Computers 19v you can't do that due to three wire cord and battery monitoring in 
the supply. What you can do is Choke them. Buy some FT-240 #31 mix ferrite 
cores. Add a 6 foot extension cord to the AC side of the computer supply. This 
gives you a reasonable amount of AC power cord to wrap through a stacked pair 
of these Cores. Then the same mix 31 but smaller diameter and a pair of those 
wrap as many turns as you can through that pair for the low voltage lead to the 
computer. The above works well on a couple of my Dell Laptops.

John k9uwa

> Hello,
> 
> I´ve followed the recent threads, including the "replace switching supplies
> & wall warts with linear ones".
> 
> Agree, that´s (relatively) easy to do with 12 volt devices (linear supply,
> battery, etc.).
> 
> What would you recommend for 19 volt items (laptops, intel NUC, monitors, other
> devices), and distribution system for same?
> 
>  * Prefer battery backup ("float a 19 volt battery" or w/e)
>  * Prefer to avoid fan noise (e.g., HP 6023A 20V/30A/200W is nice, but too
>  noisy) * Avoid the standard 12 volt power pole convention * Some (many?) laptop
>  supplies sense the battery capacity to adjust charge characteristics (3rd pin)
>  * Probably other concerns to think about :)
> 
> A google search shows several that apparently confuse "in - line" (that is,
> not inside the computer) with "linear" (as in, non-switcher).
> 
> My guess is that there are several (?) switchers inside the laptop, monitor,
> NUC, so perhaps it is a low (or non-existent) ROI project?
> 
> Thanks,
> Scott
> W7SLS
> 
> 
> 
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John Goller, K9UWA & Jean Goller, N9PXF 
Antique Radio Restorations
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