It uses a fixed frequency crystal oscillator, you would have to desolder that and wire in an adjustable clock source to try any sort of overclocking.

I don't actually own one of these as they are way overpriced even at the new lower price.
But every screenshot I have seen show lots of hardware errors when mining.
Isn't that a sign that they are already overclocked way to high?

You can only mine SHA256 coins btw, not other alts. As for this - the chips themselves run on <2v so it may be a regulator limit and supplying more amperage on the USB socket/5v line may not actually help at all.

Anyway, would anyone with one already care to read off the crystal speed? Also the voltage regulator part number would be interesting, voltage reading even better, and maybe a current reading of what is being pulled over the USB. Then we could work out exactly how much headroom we have. An unlimited current supply on the 5v might help if the regulator has a decent amount of headroom.

...although I feel like the new ones say Rev. 3.00 on the back...

Looks like someone has blanked out the power mosfet though, gonna have a search for third party images...

It's an inductor used in the power supply circuit for the ASIC chip

That 11(ish) one is connected directly to the USB interface chip so that one is far less likely to be the base for the clock speed. As for that power supply, looks to be this:
http://www.aosmd.com/pdfs/datasheet/AOZ1021AI.pdf

That part is rated at 3a output, the USB spec says a max of 2.5watts so as long as the chip is supplied at >1v there should be a bit of headroom left, especially once you take into consideration that some of the power draw is the buck conversion inefficiencies not the ASIC itself. Would definitely require a re-wired/modded USB hub though.

To work out the exact Vout to the ASIC either measure voltage out across pin 3 and the 'far' side of R1 whilst running (riskier), or measure the resistance values of R1+R2 whilst off and check against that datasheet. (pinouts and supporting circuitry p12/13, voltage programming table p7)

The resistance offered by the multimeter is usually 1 or 10megaohm so it shouldn't disrupt the circuit at all. Just yeah try not to touch the wrong thing/slip whilst measuring! If you did both measurements you could check the voltage sag compared to what it has been set to with the resistor values.

Also need to work out how the clocking works/clock multiplication ratio. It is probably  be the 11.0592MHz( x 30 ) going into "IC3" which I can't seem to find a datasheet for. 12mhz is normally used for USB but is connected to the ASIC directly...

And yeah that's what I meant on the hub, just be careful as there should be decoupling capacitors in there that would complicate things; make sure you're only reinforcing existing connections and not making new ones!

You'll definately need some better heatsinking btw. Definately look into getting something like these for both sides of the device, ASIC and VRM. Might need to cut them up on the component side though.
 http://dx.com/p/aluminum-cooler-heat-sink-chipset-for-ram-memory-w-type-8-piece-set-35816

 If they overclock enough I might buy some if ROI looks likely, was planning on mounting them on an old CPU cooler!

R1 = 603R
R2 = 1058R

I make that 1.25V or 2.2V, depending on which way around the 2 would be.  They aren't K ohm though.

R3 = 7.45K
R4 = 3.36K

These give 1.16V with the formula, but I can't tell where the vias go as the other side of the circuit board is an aluminium plate, so I am not sure which of these 4 are the ones.  R3 and R4 are the only ones in the K ohm range out of the 4 nearby though.  I can see R1 is the one on pin 4, so it must be one of the 2 in the divider circuit.

Measuring the voltage from pin 3 to the opposite side of R1 (where the via is) gives 1.04V.


IDK WTF is going on, but then I am a software engineer who has to drive hardware, not design or debug it.