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I'm using this image on my 110, and I decided to do some voltage modification. I figure I'd post this here as well. I edited index.php to get different clock speeds.
So far 24 hour testing of 1320MHz has been successful. With 5 blades overvolted and clocked at 1320MHz, and one at stock voltage and 1200MHz, I'm getting an average 110MH/s pool side.
So I decided to take a crack at overvolting and overclocking my A2 110. The guide provided earlier in this thread does not cover the V4 boards, and I could not find one on the forums so I decided to post it here.
The A2 110 V4 blade buck controllers are based on Linear Technology's LTC3856. Datasheet. Following Pg 29, the feedback resistors will be connected to FB (pin 2), and dictate the output voltage via the equation Vout=0.6*(1+RB/RA). The controllers are set up to use the chip's diffout configuration, but the equation remains the same.
There are 3 different controller layouts on this board:
One side
Other side
End of blade
As we see in the photo, there are two resistors labeled 01C and 66B, 10kΩ and 4.75kΩ respectively.
This yields a stock voltage of 0.6*(1+4.75/10)=0.885V
I figure I want around 0.925V, following the target voltage earlier in this thread.
There are two ways to handle this. We can decrease RA or increase RB. I had a lot of 24kΩ and 27kΩ resistors left over from a previous project. It just so happened that if I used one of each value in parallel with each RA and RB, 27kΩ||10kΩ=7.297kΩ and 24kΩ||4.75kΩ=3.965kΩ yields 0.926V.
So I soldered a 27kΩ across the resistor marked 01C and a 24kΩ across the resistor marked 66B. I ended up with ~0.933V on average.
If you want to only solder one resistor, Rp in parallel with RA (01C), it would follow this equation: Vout=0.6*(1+(4750/(10000*Rp/(10000+Rp)))). Solve for Rp given a target Vout.
I've yet to do long term overclock testing. I'm testing 1200MHz stability for now. On average the power consumption is up ~2A to ~15A on the 12V rail. My stock power supply is not able to supply more than 4 blades stock, much less 4 overclocked blades. I just split the load half and half between the stock power supply and another 1kW power supply. I should have some numbers soon.
The A2 110 V4 blade buck controllers are based on Linear Technology's LTC3856. Datasheet. Following Pg 29, the feedback resistors will be connected to FB (pin 2), and dictate the output voltage via the equation Vout=0.6*(1+RB/RA). The controllers are set up to use the chip's diffout configuration, but the equation remains the same.
There are 3 different controller layouts on this board:
One side
Other side
End of blade
As we see in the photo, there are two resistors labeled 01C and 66B, 10kΩ and 4.75kΩ respectively.
This yields a stock voltage of 0.6*(1+4.75/10)=0.885V
I figure I want around 0.925V, following the target voltage earlier in this thread.
There are two ways to handle this. We can decrease RA or increase RB. I had a lot of 24kΩ and 27kΩ resistors left over from a previous project. It just so happened that if I used one of each value in parallel with each RA and RB, 27kΩ||10kΩ=7.297kΩ and 24kΩ||4.75kΩ=3.965kΩ yields 0.926V.
So I soldered a 27kΩ across the resistor marked 01C and a 24kΩ across the resistor marked 66B. I ended up with ~0.933V on average.
If you want to only solder one resistor, Rp in parallel with RA (01C), it would follow this equation: Vout=0.6*(1+(4750/(10000*Rp/(10000+Rp)))). Solve for Rp given a target Vout.
I've yet to do long term overclock testing. I'm testing 1200MHz stability for now. On average the power consumption is up ~2A to ~15A on the 12V rail. My stock power supply is not able to supply more than 4 blades stock, much less 4 overclocked blades. I just split the load half and half between the stock power supply and another 1kW power supply. I should have some numbers soon.
So far 24 hour testing of 1320MHz has been successful. With 5 blades overvolted and clocked at 1320MHz, and one at stock voltage and 1200MHz, I'm getting an average 110MH/s pool side.
You're rocking it!!!
