bbking67 Posted September 4, 2013 Share Posted September 4, 2013 (edited) Some of the cheaper chargers seem to have voltage dips under load which renders them useless... there are some youtube videos showing this in the context of powering Raspberry Pi devices. I think that some motherboards have a "special" charging port that will provide more current... I have a motherboard like that and I use it to revive my HP Touchpad. My Touchpad (running Android 4) has this quirk that when the power level drops too low you can't charge it with a charger. Somehow a regular 2A charger isn't enough to wake the unit up, but the Asus motherboard can. Strange. Anyway, this feature supplies 1.2A, so it might not be enough for Atari's anyway. I'm not too sure why anyone would want to charge with a PC anyway. Edited September 4, 2013 by bbking67 Quote Link to comment Share on other sites More sharing options...
toad Posted September 4, 2013 Share Posted September 4, 2013 The fact that this cable isn't "good" (but will plug in) with many (most???) PCs but *IS* good with a known-good chargers (1.5-2amp) from a reputable supplier should have been emphasized. Should it not have been? Happier customers (due to disaster-avoidance) would be the result. Would it not? To be fair to the seller he/she said in the auction "require minimum 1.5 amp USB power source" and "Power supply/adapter not included" I didn't take that to mean, plug it into a PC for power. The discussion of how some chargers have poor quality is great to discuss here, but I don't believe its appropriate within the auction listing. Poor wiring in your house might cause a fire or destroy your tv - so - don't buy tv's? Stick with radio? I find this whole discussion about danger perhaps a little unfair, because I would be very surprised if his product is dangerous at all - but I'm fixing to find out only 2 more days.....yeah, can't wait. Quote Link to comment Share on other sites More sharing options...
+wood_jl Posted September 4, 2013 Share Posted September 4, 2013 toad, you are correct, in the fact that he said that. But of course many people don't have a clue as to the capacity of their computer's USB ports, and it's very tempting to plug it in. I felt some stronger wording would help in this regard, but I think it is an EXTREMELY cool cable for opening up the world of [decent] USB chargers to replace faulty old 800XL power supplies!!! Please post your findings when you receive your cable! Quote Link to comment Share on other sites More sharing options...
toad Posted September 5, 2013 Share Posted September 5, 2013 Yeah in retrospect I think you are right. He says many household devices have usb power - well, I would think the most common of all is a computer. He may want to mention either not to use it with a computer or how to do so. Actually my computer near the Atari - at the moment is a Dell XPS 8700 with 2 completely unused USB 3.0 ports . Since USB 3.0 is spec'd at 900ma - I guess I could use a y-cable and power the Atari from the Dell. And if I was using the Dell as a APE server - it might even be quite handy to do that....hmm But I'm personally not going to keep the Dell dedicated to the Atari...I'm getting rid of the Dell -too many computers in my collection, lol... Quote Link to comment Share on other sites More sharing options...
Rybags Posted September 5, 2013 Share Posted September 5, 2013 I've got 5 or 6 USB chargers which range from about 500 - 2000 mA (Nexus 7 charger). Been thinking myself about making such an adaptor, the 1 Amp adaptors should run practically any unexpanded machine. Given that so many cheap electronic devices these days are USB chargable a DIY cable can be a simple case of repurposing an old cable and simply soldering a $1.50 DIN plug onto the other end. As for running from a PC's USB port/s, depends on the motherboard. Additional to higher current with later versions, some modern boards even allow supplying power when the machine is in standby or powered off. Of course there's always the alternative used by some small external HDDs, use 2 cables so you're getting half the required current from each port being used. Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 11, 2013 Share Posted September 11, 2013 So I got my cable and I purchased this USB adapter: http://www.amazon.com/Anker%C2%AE-18W-3-6A-Wall-Charger/dp/B00B8L36A6/ref=pd_cp_cps_3 No go............I get the red power light on my 130XE and 800XL but the READY screen is green. It wont show anything if a cart is plugged in which means not enough juice...... So - anyone have a suggestion on a USB adapter that can put out the amps needed for this baby? Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted September 11, 2013 Share Posted September 11, 2013 3.6Amp and not enough amps - i dont think so. Try regulating the current with a resistor on the power leg so that no more than 1.7 amps (say) is capable of being drawn. Others may disagree but i dont see why an atari would survive with more without becoming a toaster. Quote Link to comment Share on other sites More sharing options...
bbking67 Posted September 11, 2013 Share Posted September 11, 2013 I think phone chargers aren't as good as, for example, using a 5V adapter from a router (easy to find at value village, 2.5A and should not drop voltage like some cheap chargers). Quote Link to comment Share on other sites More sharing options...
+Stephen Posted September 11, 2013 Share Posted September 11, 2013 3.6Amp and not enough amps - i dont think so. Try regulating the current with a resistor on the power leg so that no more than 1.7 amps (say) is capable of being drawn. Others may disagree but i dont see why an atari would survive with more without becoming a toaster. The reason others say it will survive with more amps, is because unless you have something in the Atari causing a short, it will only pull the amount of current needed. You can hook a 500 AMP car battery to a 12V light that uses .5AMP, and the battery will not push 500 AMPS through the light - the light will only pull .5AMP. Quote Link to comment Share on other sites More sharing options...
toad Posted September 11, 2013 Share Posted September 11, 2013 I got mine in - no issues, works with carts & its an expanded Atari 800XL with VBXE card. I'm currently using the Samsung Galaxy Note II charger. It's a 2amp. I haven't been able to do much with my Atari hobby for a couple weeks - blast, but work is keeping me busy. Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 13, 2013 Share Posted September 13, 2013 So I tried my ASUS T101 USB Adaptor which is rated at Output:5Vdc/2A and same result, a green screen READY. I presume the green background indicates some sort of power issue cause when the regular power supply is used the background is the standard blue. Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted September 13, 2013 Share Posted September 13, 2013 (edited) too much power me thinks... Edited September 13, 2013 by Magic Knight Quote Link to comment Share on other sites More sharing options...
+Stephen Posted September 13, 2013 Share Posted September 13, 2013 too much power me thinks... http://bit.ly/Ka8BsV Please study this before posting again. 1 Quote Link to comment Share on other sites More sharing options...
foft Posted September 13, 2013 Share Posted September 13, 2013 (edited) With a potential difference (voltage) over a resistance the current(amps) comes from the equation I=V/R. Where I is current, V is voltage (from psu) and R is resistance (of Atari). So a power supply that is capable of supplying more current is not a problem since 'R' is a property of the Atari and 'V' is a property of the psu. This assumes constant resistance from the Atari (true-ish). This also assumes constant voltage from the PSU. Approx true for a regulated supply where psu current rating > required current. Not true for unregulated psu. With an unregulated psu driving a low current the voltage can be wildly higher and at a high current lower. I suggest making sure the psu is regulated. So look for 5V, > 1.5A and regulated. Edited September 13, 2013 by foft Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 13, 2013 Share Posted September 13, 2013 Ok - that is all great and everything but Im not good with ohms and electricity. Just hoping someone could point me to a USB adapter that should work with this thing, or the spec's I need to look for. Most said output shouldnt matter cause the computer will only pull what it needs, seems like that is not that case. The first adapter I got was rated at 3.6A I dont think it is putting out that much since my ASUS tablet wont charge with it - most likely each port gets 1.3A.........false advertising. Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 13, 2013 Share Posted September 13, 2013 With a potential difference (voltage) over a resistance the current(amps) comes from the equation I=V/R. Where I is current, V is voltage (from psu) and R is resistance (of Atari). So a power supply that is capable of supplying more current is not a problem since 'R' is a property of the Atari and 'V' is a property of the psu. This assumes constant resistance from the Atari (true-ish). This also assumes constant voltage from the PSU. Approx true for a regulated supply where psu current rating > required current. Not true for unregulated psu. With an unregulated psu driving a low current the voltage can be wildly higher and at a high current lower. I suggest making sure the psu is regulated. So look for 5V, > 1.5A and regulated. Thanks - Ill see what Amazon has. Quote Link to comment Share on other sites More sharing options...
Magic Knight Posted September 13, 2013 Share Posted September 13, 2013 http://bit.ly/Ka8BsV Please study this before posting again. better still, i will stay out of this thread. Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted September 13, 2013 Share Posted September 13, 2013 The first adapter I got was rated at 3.6A I dont think it is putting out that much since my ASUS tablet wont charge with it - most likely each port gets 1.3A.........false advertising. You are correct. One port is 2.1A and the other is 1.5A (zoom the attached pic). These are a bit misleading, but most of the multiport adapters state the total amperage from all ports in their title but each port only generates a portion of the total. Still, at 1.5A and 2.1A, either port should power the Atari. Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 13, 2013 Share Posted September 13, 2013 You are correct. One port is 2.1A and the other is 1.5A (zoom the attached pic). These are a bit misleading, but most of the multiport adapters state the total amperage from all ports in their title but each port only generates a portion of the total. Still, at 1.5A and 2.1A, either port should power the Atari. 61VA3-Aoj1L._SL1500_.jpg Neither port worked - maybe the cable I got is bad? Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted September 13, 2013 Share Posted September 13, 2013 Neither port worked - maybe the cable I got is bad? That would be the next thing I'd check, especially if the computers works fine with an original supply and you've already tried different computers and power adapters. The only thing you haven't tried yet is a different cable. Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 13, 2013 Share Posted September 13, 2013 Original PS works fine - when I use the USB power cable with any USB adapter I get a green READY screen Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted September 13, 2013 Share Posted September 13, 2013 Also, There are 3 pins that feed +5V. I'm not sure on the computer side but if the 3 pins feed 3 separate circuits in the Atari, one dead pin could cause issues in certain areas (video???). If the 3 pins are joined or bridged in the Atari or the PS, then it wouldn't matter. Same goes for the ground pins, but those should be bridged. Quote Link to comment Share on other sites More sharing options...
+Stephen Posted September 13, 2013 Share Posted September 13, 2013 Original PS works fine - when I use the USB power cable with any USB adapter I get a green READY screen It will be tough to figure this out without opening the Atari, and measuring the voltage at the power jack, with the machine powered on. Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted September 13, 2013 Share Posted September 13, 2013 So I got my cable and I purchased this USB adapter: http://www.amazon.com/Anker%C2%AE-18W-3-6A-Wall-Charger/dp/B00B8L36A6/ref=pd_cp_cps_3 No go............I get the red power light on my 130XE and 800XL but the READY screen is green. It wont show anything if a cart is plugged in which means not enough juice...... So - anyone have a suggestion on a USB adapter that can put out the amps needed for this baby? So, where did you get the cable?? Do you have a link?? Quote Link to comment Share on other sites More sharing options...
Goochman Posted September 13, 2013 Share Posted September 13, 2013 So, where did you get the cable?? Do you have a link?? From this ebay listing: http://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&pub=5574883395&toolid=10001&campid=5336500554&customid=&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2FAtari-600XL-800XL-65XE-130XE-XE-GS-Game-System-USB-Power-Adapter-Cable-Tested-%2F331009703144%3Fpt%3DUS_Vintage_Computing_Parts_Accessories%26hash%3Ditem4d11b73ce8 Quote Link to comment Share on other sites More sharing options...
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