exxos's Atari, Amiga & retro forum

Reaching the completion of placing the components on the PCB, and I found some changes to apply to the 32Mhz clock and modulator clock circuit :

• a C67 that does not appears on the schematic (neither in the same circuitry on the STF and STe), and I forgot R140. My guess is that it was present in the initial circuit but quickly deemed unnecessary. But that it was not removed from the PCB.
• a forgotten R140 between U41 and the base of Q11

Recently I got inspired about how I want to implement the powering of my STE using a USB phone charger (see experiment there : viewtopic.php?f=9&t=5939)

Instead of doing 3dmodeling of 3d printed parts, I decided to reuse the original mount bracket, and replace the psu board. Then I would hack an IEC 60320 C13 plug to feed a DC5V through it. Thus, no casing, plug or power switch mistreated


I'll have to check what I could order at mouser to get the free shipping, so not before end of september for the next step...

Oddly I managed to power my H5 from the USB port from my PC :lol:

exxos wrote: 25 Aug 2023 15:35 Oddly I managed to power my H5 from the USB port from my PC :lol:

That makes it a quite huge power supply :D

A little micro-step forward for my project of DC power supply for my STe : I hacked a IEC 60320 C13 and put a 55-21 barrel jack connector, so that I can either use a usual power brick (I found one on amazon, 5V at 4Amps, that I have to test), either a USB power delivery trigger with a suitable jack connector. I used the plastic flexible sleeve, that fit the barrel jack connector, to position it correctly.

Nice :dualthumbup:

sporniket wrote: 24 Sep 2023 15:49 A little micro-step forward for my project of DC power supply for my STe : I hacked a IEC 60320 C13 and put a 55-21 barrel jack connector, so that I can either use a usual power brick (I found one on amazon, 5V at 4Amps, that I have to test), either a USB power delivery trigger with a suitable jack connector. I used the plastic flexible sleeve, that fit the barrel jack connector, to position it correctly.

Wow. Very cool. I guess you are not selling this, otherwise I want at least a couple!

Thanks for your kind words.

@ijor I plan to get parts, assemble a few units and perform some trials during next month. I take note of your interest.

This evening, I was feeling like setting up my scope, my electronic load, and test my 5V/4A/20W power brick to check that it will be good enough to power my STe :

• I got the electronic load here : https://fr.aliexpress.com/item/4001153199791.html
• the power brick is from there : www.amazon.fr/dp/B01HRR9GY4

I started with measuring the voltage when the load requires 2A of current. The voltage is in the 5-5.2V range, the ripples are small, and there is no spike :


Then I setup the load at 3.9Amp to see how it goes near the limit of the power brick. The voltage drops a little bit under 5V (around 4.8V).


Then I setup the load at 3.8Amp, with the intent to let it work for an hour.


The voltage is a little bit more close to 5V, but the average is quite the same as at 3.9A. It's better at 3.7/3.6A and below.

Also, after one hour powering the load at 3.8A, the temperature of the brick is warm (I have a K-probe thingy, it is in the 45-50 degrees)

Thus I conclude that this power brick will be safe enough for my experiment to come.

Do electronic loads cause "noise" on the rails it's powering ? I've never used a electronic load. So don't know how it compares to a resistor load.