Can someone post details/pictures of the 5v fan mod? Is there another point to solder the fan leads to? Is it dangerous in any way (dangerous in terms of load to the newly utilized power circuit)?
Speaking of Fan mod...for silent operation...:
With all my due respect to Wolfey's solution...There is another "Classic Silent fan" solution from the CPU overclocking experience...7V fan driving...between 12V and 5V power lines...
How...: Disconnect the GROUND/BLACK wire from the original position...and solder back to the 5V regulator uP1707 output...this is the small / medium size 8-pin chip to the left of the 12V PS supply connector...the easiest point to connect are to the big output SMD caps to the right of the IC...C201/C203...their pins towards the center of the board...facing the square inductor close to them...this is 5V output supply...uP1707 is rated for up to 3A...so the current load of the fan should not have any effect on the circuit...
Mine is running whisper quiet @ 6.69V...11.82V - 5.13V ...
IMHO this is better solution ...because of the higher voltage...better performance/cooling...but still silent/no noise...not creating ANY load to 5V USB supply, preventing possible issues with USB hub(s) with many Gridseeds...not having enough juice...etc...
As usual...try at your own risk...
Cheers,
ZiG
P.S. I am assuming that everybody, interested in these mods, has already PDF schematics of the 5-chip Gridseed device from...:
https://github.com/gridseed/usb-miner/tree/master/hardwarePersonal preference, is what comes to mind. Tinkering is the other thought.
Someone just had to find a different method / solution to a problem that has already been solved.
Their solution is actually 'in reality' not a solution, but another PROBLEM! And potentially hazardous to the pods health! It could blow the whole smash and brick your pod!
There is little to no additional demand being put on the USB power supply end. .078 'Milli' Amps is NOTHING!
Yes, it adds up but still, even with 10 GS5's it's only 780mA, with 20 it's 1.56A which is nothing for a USB power supply, supplying 2.5A to 5A to the USB hub etc. Being fed 5V from the rail of a PC psu is even more robust power wise.
There is no noise on the fan line that can disturb or harm the USB drive circuit and definitely ZERO noise or EMI of any kind interfering with USB data operations either.
There is enough CFM of air being pumped by the fan at 5V to keep the pod cool enough while running in Scrypt only mode.
It is common knowledge as well as recommended by and instituted by the manufacturer that every USB hub should be powered by at least a 2.5A to 5A power supply due to all the pods it's powering in the first place. There is TONS of headroom for the addition of .078mA per pod, if properly powered in the first place.
USB power is MADE to do what it is doing by supplying 5V to the fan.
One other important observation is, the connections made via the 12V rail and the voltage regulator is what's called a floating ground or feedback LOOP which is why the power fluctuates as per your voltage measurements of "6.69V...11.82V - 5.13V" ...
? This variance is an indication of improper and unstable power supply from the voltage regulator and most likely being caused by other electronics pulling power from it such as the processor chips themselves! DANGEROUS! BAD IDEA! DO NOT TRY IT! It's actually causing the fan to try to close the loop in its quest to find GROUND or +
The pretty quiet little fan is now in danger of making magic black smoke and bricking your pod!
DO NOT CONNECT POWER TO THE FAN THIS WAY THROUGH THE VOLTAGE REGULATOR!It's not actually connected to a 'real' - ground source. It's floating and that is dangerous in itself and could harm the electronics of the pod if the fan goes bad or there is a short.
It's not a valid solution electrically speaking the way it is powered on the 12V rail side using the Voltage Regulator as a floating ground connection. That is not what it's made to do.
The USB power solution IS VALID because it's made to supply power to small DC motors as well as electronic driver circuits, such as it is! The air flow supplied by the fan via 5V USB power us perfectly fine and sufficient to do what ever little bit of cooling it has to do!
Please, just leave well enough alone! Words like "if it ain't broken, don't fix it" comes FIRMLY to mind!
How confident am I of the 5V USB solution? 100%!
And if powering your pod's fan via my 5V USB power mod bricks your pod or burns out your fan, I'LL BUY IT!
Just make sure you use a good power supply to feed all those pods their USB juice in the first place.
It's required with or without the fan mod anyway.
But if you brick or break it while making the mod, it's $ALL$ on you!