[arm-allstar] One of two USB URIs dropping off

David McGough kb4fxc at inttek.net
Sat Jan 12 22:11:06 EST 2019

Hi Mark,

Yes, that style power supply is available from many sources. And, it's
becoming the "preferred" variety for me, too, at this point.

At least if it's not potted in epoxy, the manufacturer can't hide what 
components were used!

I've also soldered power wiring to all my production RPi boards. I don't 
use the micro-usb at all.

73, David KB4FXC

On Sat, 12 Jan 2019, "Mark G Thomas via ARM-allstar" wrote:

> Hi,
> I use these cheap tiny adjustable DC-DC supplies, just a couple dollars 
each on eBay, fed with 12-14 VDC. So long as your 5V wires are short and 
heavy to minimize resistance and hence variation with load to the Pi, you 
can then adjust the supply up to sufficient voltage (possibly as high as 
5.2-5.4 – I should measure...) that you measure 5.0 or 5.1 volts on the 
test point directly on the Pi PCB. Google for where exactly to measure. 
There is a poly fuse and maybe other sources of voltage drop on the Pi; 
hence the need to use a greater than 5V supply, especially on the more 
power hungry 3B+! This works great! 
> My experience was the fixed voltage epoxy potted 12V-5V converters are 
too low voltage an output when under load, considering the resistive loss 
of the 3B+ setup.
> Mark G Thomas
> I am not sure if the photos will make it:

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