I've had USB issues before on the RPi (other miners though) and did that mod, which in my case helped.
However if it _is_ the red wire depends on the cable manufacturer. The first cable I tried they seemed to think that red is just a pretty colour and used it for data, instead of + . To be sure you either have to do trial and error or check continuity with a multimeter.
Another problem is if your hubs are made close to the original USB spec they will expect 5V from the host otherwise they won't turn on. Of course that was the case for me, so I ended up making a Y-cable where data only was on the cable from the Pi and spliced another cable into the main cable coming from an USB wallwart for power only. I hope this makes sense to you.
OK, I started looking online for something to save me butchering my brand new hub lead.. I found some quite interesting stuff actually:
This is Mini to Micro but seemed to fit the bill perfectly, with an off/on switch to boot!
This has a brilliant name, but initially I thought we need the reverse of this, no power, just data. I understood we still need a ground just also with a switchable +5v.
I couldn't find what I was looking for so understanding the connections, I decided to let rip and experiment:
http://www.moddiy.com/product_images/uploaded_images/patillaje-conector-usb.jpgI found an old Type A to Type B USB printer lead, and hacked it in half. I can confirm the lead colours were as expected. So I soldered away at the White, Green and Black leads, then insulated them whilst insulated the two pieces of Red apart from each other, twisted some silver foil around the leads and wrapped insulating tape around the whole thing. Proper job or so I thought.
Upon testing in the RPi, no devices have been found, thinking I must of not correctly soldered the connection I painstakingly took the whole thing apart again and seemingly it looked like I had messed up a connection. Yet my multimeter confused me because it said I was getting continuity so this time I just twisted the ends together and tested again with the RPi.
Again, no devices found. OK, I twisted the Red lead together and voila, the RPi found my hardware and everything worked. So then I wondered if it still needed the Red wire connected once it was up and running. I seperated the two Red wires apart from each other and bosh. CGMiner fell over with a hardware error.
https://i.imgur.com/6xItV5F.jpgThis must mean these DLink hubs are close to the original USB spec and do require the 5V to work, looks like I'm going to be making a Y cable then. Initially I didn't understand what you meant by "USB wallwart" by Google showed me
this which explained it to me.
Rather than doing that, I would prefer to use one of
these as I have a spare one laying around the house. Then I can just splice from any USB cable into my pre hacked printer cable. It's getting late here now, so it'll be a job for tomorrow.
I would place the sticks in a way that allows the hot air to go up freely. Either upwards or on the side.
As for this idea, although it does sound like a great idea, but it does seem a bit involved for just 8-10 Block Erupters. I was thinking along the lines of a large metal cylinder (like a biscuit tin) raised up off the ground on legs by a couple of inches (to allow airflow in from the bottom) then a fan blowing air up through the biscuit tin and out the top. Cutting horizontal rectangular slots to fit the hubs through the sides so the the Block Erupters are contained within the tin and have a whirlwind of cold air blowing through them. Like I say, I think I'm over complicating things.
To be honest the hottest part of my current setup is my power adaptors sockets for the two DLink hubs, and even they aren't that hot.
I'll update this post tomorrow, once I've worked wonders making a Y cable.
Thanks for the info.
