USB PSU

[Kyle22]

1 hour ago, ClausB said:

Could the Zener not be added to an XL?

I think it could be easily added to 1200 and 14x0's. The 600XL and 800XL have no 12v supply, so no good there.

 

[+mytek]

1 hour ago, ClausB said:

Could the Zener not be added to an XL?

It could if there were a good amount of excess voltage, but the voltage doubler's inefficiencies probably limit it's output to around 9 VDC. I think it takes at least 8 VDC to have the color pot circuit work reasonably well. If you could find a precision temperature independent zener rated for 8 V it could likely work. However I don't think you'll find a zener diode rated for that voltage, or if you do, I doubt that it has temperature compensation like the 10 V one I used in the 1088XLD.

 

Edit: Although this has possibilities LM341 Adjustable Precision Shunt Regulator.

 

[Sugarland]

2 hours ago, mytek said:

Edit: Although this has possibilities LM341 Adjustable Precision Shunt Regulator.

 

 

Oh I love it when you talk like this. ?

 

[marauder666]

21 hours ago, Lastic said:

Which Cisco PSU are you referring to ? I have a lot of Cisco gear so might be an interesting option.

PE-1170-1SA1

 

Not sure what device they were used for.

[Bee]

FWW - I got rid of My brick for a power strip:

 

https://www.amazon.com/gp/product/B07VM5DJS7/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

I have bought 3 of these already - 

 

https://thebrewingacademy.com/collections/atari-800-xl-xe-xel-xld/products/atari-xl-xe-replacement-power-via-usb

 

Yes I could make my own, but they are made better than I would and are off the shelf.  

 

This set up is able to run multiple A8's and the CRT's I'm using. 

 

I hope that helps

 

Thank you 

[Daedalus2097]

I've been using a Raspberry Pi supply on my 800XL with a Biggus Dickus attached too for a while and that's been working perfectly - no sign of any interference or anything, though I did replace the capacitors in the 800XL when I was fixing it up so that might have helped combat any potential noise.

 

One other thing that's worth looking at is the connections themselves - the DIN socket on the motherboard, and the DIN plug if you're reusing an original PSU one, could have loose or tarnished contacts which present an increased resistance on the 5V rail. The effect of such a resistance is to introduce a voltage drop that increases as the power draw increases. With the original PSU providing the correct voltage this is less likely, though it's still worth looking at in case there are surface or mechanical differences between the two DIN plugs used (e.g., pin diameter slightly smaller, pins on original PSI slightly bent to increase contact pressure...)

 

Aside from that, the length and thickness (well, cross-sectional area) of the cable will also contribute a resistance to the circuit. It's possible that a long, thin USB cable simply presents too much resistance to carry that much current. For example, a resistance of just 0.25 ohms in the cable will give you a voltage drop of 1V over a cable at 2A (since the resistance also counts on the ground return).

Edited January 6, 2020 by Daedalus2097