Title: Computer psu and usb 5v rail issues Post by: russells55 on January 06, 2019, 02:47:17 AM Hi hi.
I have a little project on the go. I took an old PC tower. Gutted pretty much everything but the PSU out (no mother board . Dvdrom etc) I have a put in 2 grid blades for mining. And so a pair of 2pac geeko science usb miners The grid blades need 12 volt power. So i just cut into one of the many 12v supply lines one is off a molex other from a feed to the old Motherboard. Im told they use about 75watts each Then a raspberry pi3 controls it. They work like a charm! As for the usb miners. I have a pi 1 control them in the case too. They are both plugged into a usb powered hub. At 175mhz there pulling 6-8watts (i have a meter to track it) However the voltage is terrible. With NO load its 4.99v right at the usb miner stick , on but idle. If i check other 5v feeds off the psu closer and before my grade 8 soildering skills i get 5.06v to 4.99v That would all be ok but with one usb miner running. The voltage drops too 4.71v. With both 4.22v Then the sticks sooner or later crash (or atleast 1 will) I have tried 2 usb other hubs. Other 5volt feeds off the PSU Still the huge voltage drop. I also found a random power plug i think for a very old portable house phone rated 5volt 3A. It test 5.08volt I plugged that in the hub as the power And with both sticks running it drops to 4.89v at the stick. This is a 480watt computer psu. Any idea why it cant handle powering a usb hub? Russ Title: Re: Computer psu and usb 5v rail issues Post by: VasilyS on January 06, 2019, 11:26:58 AM You need to use a USB hub with external, separate mains power. This will remove the load from the computer's power supply.
Title: Re: Computer psu and usb 5v rail issues Post by: philipma1957 on January 06, 2019, 01:23:51 PM Hi hi. most likely a garbage generic psuI have a little project on the go. I took an old PC tower. Gutted pretty much everything but the PSU out (no mother board . Dvdrom etc) I have a put in 2 grid blades for mining. And so a pair of 2pac geeko science usb miners The grid blades need 12 volt power. So i just cut into one of the many 12v supply lines one is off a molex other from a feed to the old Motherboard. Im told they use about 75watts each Then a raspberry pi3 controls it. They work like a charm! As for the usb miners. I have a pi 1 control them in the case too. They are both plugged into a usb powered hub. At 175mhz there pulling 6-8watts (i have a meter to track it) However the voltage is terrible. With NO load its 4.99v right at the usb miner stick , on but idle. If i check other 5v feeds off the psu closer and before my grade 8 soildering skills i get 5.06v to 4.99v That would all be ok but with one usb miner running. The voltage drops too 4.71v. With both 4.22v Then the sticks sooner or later crash (or atleast 1 will) I have tried 2 usb other hubs. Other 5volt feeds off the PSU Still the huge voltage drop. I also found a random power plug i think for a very old portable house phone rated 5volt 3A. It test 5.08volt I plugged that in the hub as the power And with both sticks running it drops to 4.89v at the stick. This is a 480watt computer psu. Any idea why it cant handle powering a usb hub? Russ here is a link to a quality 5 volt psu that has voltage control https://www.trcelectronics.com/ecomm/pdf/lrs75.pdf it will do 3 sticks and give 15 watts a stick you could set to 5.5 volts which will sag to 5.1 or 5.2 as they all sag sidehack has built a good usb hub can do six sticks at 10-15 watts I personally use this one https://bitcointalk.org/index.php?topic=5053711.msg48725753#msg48725753 https://www.eyeboot.com/sipolar-10-port-usb-hub.html Title: Re: Computer psu and usb 5v rail issues Post by: russells55 on January 06, 2019, 01:40:20 PM The is Psu is a Actec neo480
https://www.newegg.com/Product/Product.aspx?Item=N82E16817103924 The 5v rail is rated for 38A i and using what 5A. Could a dc to dc buck converter help here. If i Bring the voltage to 5.2 or something. I noticed on my good usb power adapters like the one that i have for the raspberry pi the voltage output is 5.19v Or 5.16 on a phone charger i have. Do you think supplying say 5.25volts to the hub is a good idea? Cheers Title: Re: Computer psu and usb 5v rail issues Post by: philipma1957 on January 06, 2019, 07:18:10 PM The is Psu is a Actec neo480 https://www.newegg.com/Product/Product.aspx?Item=N82E16817103924 The 5v rail is rated for 38A i and using what 5A. Could a dc to dc buck converter help here. If i Bring the voltage to 5.2 or something. I noticed on my good usb power adapters like the one that i have for the raspberry pi the voltage output is 5.19v Or 5.16 on a phone charger i have. Do you think supplying say 5.25volts to the hub is a good idea? Cheers if you add this it is 12 dollars https://www.amazon.com/Converter-DROK-Regulator-Adjustable-Transformer/dp/B06XG2KPTS/ref=sr_1_3? set to 5.3 or 5.35 or buy this https://www.trcelectronics.com/mean-well-power-supply-lrs-75 https://www.trcelectronics.com/View/Mean-Well/LRS-75-5.shtml it is 15 dollars 86% efficient or buy the hub I used. Title: Re: Computer psu and usb 5v rail issues Post by: DocDrydenn on January 10, 2019, 12:59:32 PM I'm glad to hear that I'm not the only one still running these USB ASICs.
I've currently got the following running on one of my rigs: 4x GekkoScience 2PAC 2x Gridseed Orb 1x Blizzard Zeus 1x Futurebit Moonlander 2 1x Nanofury NF1 1x GTX 1070 1x GTX 1060 1x RX 570 (Hell, I even mine cryptonight_heavy on the two Xeon X5670 CPU's in this rig.) For the ASIC's, I went with two Plugable USB 2.0 7-Port Hub with 60W Power Adapter's I got on sale from Amazon. https://www.amazon.com/Plugable-7-Port-Speed-Charging-Adapter/dp/B00L2LK164/ref=sr_1_1?ie=UTF8&qid=1547123579&sr=8-1&keywords=B00L2LK164 (https://www.amazon.com/Plugable-7-Port-Speed-Charging-Adapter/dp/B00L2LK164/ref=sr_1_1?ie=UTF8&qid=1547123579&sr=8-1&keywords=B00L2LK164) I'm running all this (9 different hardware devices across 9 different software miners) on PiMP OS (a Linux-based mining OS). Title: Re: Computer psu and usb 5v rail issues Post by: russells55 on January 10, 2019, 01:06:39 PM What is your voltage on say the 2pac sticks when running.
Does the hub stay at say 5.1v always or anything like that? |