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Sugarland

Powering XL's & XE's off of USB phone chargers, etc

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Hello Atarians,

 

Is this a bad idea? See attached photo. I tested it and my 130xe (with no mods) works when plugged into my 1amp Apple phone charger. I wonder if Steve Jobs turned in his grave. I cut the plug off of an ingot PSU. Should I remove the RFI filter? I presume it's not needed but it might not hurt. I don't have an oscilloscope scope to test ripple but the volts check out. Comments welcome.

 

The white stripe wire on the Atari cord is correctly going to positive. The USB cable had correctly color coded red and black wires. A lot of these phone chargers are advertised as having over current protection, right? Anyone else powering off of USB? Are there any risks doing this?

 

What about installing a USB type B on the computer to replace the current plug? In the long run probably easier than making custom cables.

 

 

 

post-49049-0-39553600-1515377612_thumb.jpg

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5 volts is 5 volts. But 1A is a little tight, I'd be more comfortable with 1.5A, especially if you have any RAM upgrades, or peripherals like modems or sio2pc that tap off the computers power. It's definitely way safer than an ingot!

 

The Atari part of the cord is really thick guage wire, whereas USB is usually pretty tiny, and leads to voltage drops over a few feet. I've found below 4.7v the video output colour hue shifts. So I'd splice the cords so there's less USB cable, and more Atari cable.

 

You can measure the computer's voltage while powered on from the GND and +5V pins on the joystick ports.

Edited by Nezgar
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Great feedback thank you Nezgar. Powered off the USB cable, the joystick port tests at 4.89v at READY prompt and the same volts doing the memory self test. With the 'silver label' PSU, I test the joystick port at 5.07v. So yes it looks like the long usb cable is dropping some voltage.

 

Yes the power lines in the usb cable are thinner than the Atari cord. I will get a 'charging usb cable' soon. I see ones rated at 3A. Thank you!!

Edited by Sugarland

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Been meaning to do it for years. There's even weird premade USB to barrel type connectors on eBay so you could make something up without the annoyance of having to solder a little USB socket.

 

Many chargers are only 1.2 Amps or less though - for Atari use that'd be OK for a stock machine but for an expanded system I'd be going 2 Amps or better.

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Not all cell phone chargers are the same. I tested this idea out with the 1088XEL, and used one of those USB to Coaxial power plug adapters. Problem is only about 2 out of 6 chargers actually worked for this application. And I even bought a new Belkon 2 AMP rated one, but it failed as well. Problem is that a lot of those are not a true DC switching power supply, but are instead based on some sort of weird capacitor circuit. Which obviously works fine for charging and even a small parallel current draw, but fails to output the correct voltage for the A8 (voltage will usually be quite low). I think a lot has to do with counting on the battery adding stability to the output voltage (like a giant capacitor).

 

However those other small wall wart power adapters that already come with a coaxial power connector, do seem to work just fine, and live up to their current ratings. That's because they are actual DC switching PSU's intended for powering up a device, and not aimed at charging a battery.

 

I can vouch for this one working good at powering up a fully loaded A8 system.

 

MFG_SWI10-N_BarrelPlug_sml.jpg

Manufacturer: CUI P/N: SWI10-5-N-P5

Vendor: Digi-Key P/N: 102-4136-ND

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Yes this is what I am wondering -- if a phone charger or usb power device is designed for phone charging and not powering a device. That Digi-key psu looks good thank you I may go that route.

 

What do you think of this one? It looks like it has a real PSU in it from the photos. Specifically the 5th photo. Edit: Or this one! A pi psu.

 

I have a new Moto(rolla) USB phone charger here that should do more than the 1amp charger I tested. Can't find it right now. I'll keep looking and report back on its joystick port voltages. I will try my PC too. :)

Edited by Sugarland

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Some chargers are pretty pissweak and will suffer a voltage drop under load which mightn't be acceptable for the Atari.

 

I bought a USB charger doctor device from eBay for about 3 bucks. Good idea to get one, it alternates between Volts and Amps display.

 

I'd recommend testing a charger first - put a high demand device on it that'll try and drag the full current out of it. Phones will generally go through phases of high/low demand due to the way you should charge Li-ion batteries, so you might need to try other devices and find one that has high demand.

Or I suppose you could just use a hub and connect 2 or 3 devices at once.

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i bought a handful of of 5v adapters, cut the cable and cut the cable to the XL PSU

joined the two together and all is good

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If the charger is of a reasonable quality and can give 1,5 A, then it is a good replacement.

What matters is the quality of the PSU. Will it hold the voltage close to 5 V? Does it provide any protections? Interference?

My favorite is this one from Mean Well. (the manufacturer provides variant for 120 V, of course)

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However those other small wall wart power adapters that already come with a coaxial power connector, do seem to work just fine, and live up to their current ratings. That's because they are actual DC switching PSU's intended for powering up a device, and not aimed at charging a battery.

 

I can vouch for this one working good at powering up a fully loaded A8 system.

 

MFG_SWI10-N_BarrelPlug_sml.jpg

Manufacturer: CUI P/N: SWI10-5-N-P5

Vendor: Digi-Key P/N: 102-4136-ND

 

 

Bravo..

 

Now my next project is to rework a failed Atari 800 power board and get rid of the bad power supply caps, chop out the 5V and 12V regulators and just power the computer with a multivolt class 3 switcher supply like from a small ibm pc desktop supply. I have about 3 +5/+12VDC supplies rated for 2A each that look clean on the scope. Not pulsing, but were used to power external hard drive and cdrom drives..

 

I'll post the mod to the 400/800 internal board so you keep the SIO and video sockets.

 

Here's the supply I have.. $5.99 Amazon

https://www.amazon.com/Vktech-Adapter-Hard-Disk-Power-Supply/dp/B00D2LS2AO

Edited by mechanerd

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I hope that PSU works out. How do the volts test? A week ago I bought a similar molex PSU with the same idea. Photo attached. It tests at 5.15v. I'm not comfortable with that. Read below I think that might be too much?

 

Ironically my silver label Atari CO61982 power supply went bad two weeks ago. Three different machines here were exhibiting odd behavior like in Ultima 3 where time would skip and hostiles would appear from nowhere. Also they would fail the GTIA test but when I put my finger on it to cool it back down the test gradients would return. Also the GTIA would get hot. I had tested the silver label just a week previously and yet testing it again it was now at 5.15v from 5.07 above in this thread. So those new old stock silver labels from myatari on ebay I don't recommend those now. IMO they can fry your machine!

 

I think as mytechcontrols said, some of the usb chargers work. And I found one that works great. It came with my Moto G5 Plus phone. Has the M logo on it with TurboPower. Photo attached. 3amps and very good voltage using the cable at in the original post.

 

 

 

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post-49049-0-80507800-1517328969_thumb.jpg

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Something different, but related, back in 2013...

 

I powered a 130XE off of one of the early higher-capacity rechargeable batteries with an integrated USB charging port for powering other USB devices. Rechargeable USB batteries have become much more commonplace and evolved since then. Still, even by today's standards, the battery was a large one (18000mAh, 5"x3"x0.8"). It powered the 130XE (plus a little additional load from a 320KB upgrade) for almost 15 hours. The only oddity I had was that the color circuit was thrown off when the battery did not deliver an exact 5.0VDC, so if I didn't correct the voltage source, I had to manually compensate for it with the color adjustment on the motherboard.

 

My eventual plan was to combine it with a small LCD, and I ended up choosing one that worked well. (I had to factor in how common the vintage portable TV LCD would be for others to obtain, the quality of the display itself, the effective resolution, the overscan, how well the circuit integrated with everything else, the physical size, and +/- NTSC artifacting which was both blessing and curse, depending on the situation.) Unfortunately, the project ended up where you might have expected in 2013: without an easy way to mold a new shell and to integrate it into the 130XE case (or to replace the case entirely), it would have been a horrible kludge. With 3D printing more commonplace, it might be time to pick back up a simple portable 130XE mod. But to make it actually useful, a storage device should be integrated, too.

 

I don't know that I'll pursue the project anytime soon, but I think that the only unanswered question I'm left with today would be how to integrate some small but comfortable joystick(s) on a 130XE? And maybe if it might be better off substituting for a small panel (but that'd eat battery and make integration a far tougher challenge than just a small DIY mod).

Edited by jmccorm

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The issue with using USB chargers is that some won't deliver over 500mA current without USB protocol handshaking. This is why some older external 2.5" HDD enclosures use a Y cable which allows them to draw power from 2 USB ports.

 

I have tried several USB chargers, that work with iPhones, which are unable to charge my Android phone because they use different protocols to enable higher current.

Edited by BillC
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I hope that PSU works out. How do the volts test? A week ago I bought a similar molex PSU with the same idea. Photo attached. It tests at 5.15v. I'm not comfortable with that. Read below I think that might be too much?

If tested under load you may find a lower result.

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If tested under load you may find a lower result.

 

vdroop? Good point. I will make a molex adapter and test it. This way any PC PSU could be used for an A8. I do have a switch that will turn on the PC PSU without the need for a pc motherboard.

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When "on the road" I run my XL with a 15000mAh USB Powerbank which has four USB outlets from 1A to 2.4A. Runs without problems and the cable is very nicely made by tfhh.

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Here is a photo of a new molex cord. Volts are near perfect on my Corsair HX620w. The only problem with this cord is plugging in the molex end isn't easy. The pins get misaligned easily. Benefit is when using a quality PC PSU there are safety features and very low or nearly absent ripple, etc etc all the benefits of using a PSU designed for computer use. I will test the dedicated molex PSU (photo above) soon.

post-49049-0-32730500-1517541742_thumb.jpg

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On the ATX PSU's there is a standby power supply available which is rated at 5 VDC 2 amps which would be much safer then coming off the molex connector that you show in your adapter cable, which is more like 20-30 amps. Somewhere I did a little tutorial on how to use one of those PSU's for a 1088XEL. I'll have to find it and post a link to it. Nice thing beside it being the right amount of power you actually need, is that you don't need to switch on the PSU and/or hear it's fan running. Just plug it into the wall and you instantly have a perfectly quite 5 VDC @2 amps. And if you later do need the higher rated 5 and/or 12 VDC the tutorial also showed how to switch the PSU fully on. But hooking straight off of the high current molex plug connections to the Atari without a fuse could be deadly if anything ever gets shorted.

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