Atari XL/XE power supply questions.

[oo7]

So growing up I owned an Atari 600 XL, 3 800XL, 3 x 130 XE and 1 x XEGS

 

 

All had huge 5v power supplies. ALso had replaced 3 of the power supplies. 

 

That being said I had many revisions of power supply.

 

 

Ive also managed to run Atari 8-bits off of tiny 3rd party power supplies.

 

 

Never really looked into the inner workings of the Atari power supplies.

 

 

 

Does anyone know why they were so big? Did it have to do with having true indipendant 5 volt outputs or something?

 

I know it was long ago but even for back the these power supplies were huge so this is why Im thinking the size probably had to do with the multiple 5v outs.

 

 

 

 

 

 

[+ZuluGula]

Atari power supplies use transformer and linear regulator, which requires heat sink. All these components are big and heavy. Modern power supplies are switching type. They use much smaller transformers and don't require cooling. 

 

[Paul Westphal]

 

 

Paul

Eightbitfix.com

Edited February 24, 2020 by Paul Westphal

[+Nezgar]

The old ones using a linear transformer may be big and inefficient, but they produce very clean 5V DC power with no ripple. Many modern small switching power supplies often have insufficient filtering capacitance on the output, leaving a little bit of ripple on the 5V DC, which is visible in the video output as flickering and noise patterns in the TV picture. After 'converting' a few of these, its really hit and miss which ones are good and not so good...

[oo7]

ok thanks for the answers guys. I only ask because even back then there were power supplies that did 5v dc that were tiny. but what is said above makes sense.

 

 

[oo7]

this all being said apple usb chargers would be a good option as substitute due to the following

 

"The output of the transformer is converted to low-voltage DC, filtered, and provided as the 5 volt output through the USB port. A feedback mechanism regulates the chopping frequency to keep the output voltage stable."

[_The Doctor__]

except there is no intelligent feedback transistor/resistor combinations in the Atari like in an iphone or laptop...

Edited March 18, 2020 by _The Doctor__

[NISMOPC]

Depends on which Apple charger you speak of.

 

The earlier iPhone chargers I have from kids phones provide 5V but only @ 1A.

 

Newer iPhones use much higher voltage from what I understand. MUCH HIGHER. (I am an Android user so I could be wrong)

 

Atari XL's and XE's need at least a 5V 1.5A psu with the exception of the XEGS and 65XE. They came with 5V 1A PSU's.

 

The 400, 800 and 1200XL came with a 9V 3.4A

Edited March 18, 2020 by NISMOPC

[shoestring]

A genuine Sony PSP-100 charger are good for 5v @ 2a, a great "backup" supply for your XE/XL.

 

I say backup because these also don't produce as clean power as a linear transformer ( as mentioned above ) but it's still pretty good if you don't have anything else.

 

 

 

 

 

 

[Daedalus2097]

Chargers that use a modern USB output can produce much higher voltages, but for compatibility always start with a basic 5V output until the connected device requests a higher voltage. Which, of course, the Atari or any passive consumer won't do. And normal 5V USB chargers (and USB-C chargers in default 5V mode) have internal feedback to regulate their voltage, but not feedback from the device.

 

As for PSUs, I use official Raspberry Pi PSUs with the plug replaced on my Atari 800XLs. They're for the older RPis with micro USB instead of USB-C, so they're straightforward 5V outputs. The same output capacity as the original supply, very little ripple, and no visible interference on screen, even on a nice, clear S-video output to a Commodore 1084S monitor.

[pusakat]

2 hours ago, Daedalus2097 said:

As for PSUs, I use official Raspberry Pi PSUs with the plug replaced on my Atari 800XLs. They're for the older RPis with micro USB instead of USB-C, so they're straightforward 5V outputs. The same output capacity as the original supply, very little ripple, and no visible interference on screen, even on a nice, clear S-video output to a Commodore 1084S monitor.

 

This is very helpful info. The replacement PSU I made was scavenged from an old Android tablet charger. The ripple and interference on screen from the resulting PSU was bad, so I've been looking for a suitable candidate PSU to replace it with. Looks like I'll be buying an official RPi PSU soon.