Yeah you are absolutely right. Pencil trick just makes things worse. Even with 850mhz and voltage=1 now I get a lot of HW errors. Time to break out the eraser!
Edit: Erased and back to normal. Zero HW errors @ 850mhz. Damn - now to find someone who can solder a bridge that tiny.
Topic: GridSeed 5-chip USB miner voltage mod - page 86. (Read 156988 times)
So just bridge the section you circled? is there a resistor in place you have to remove?
There's no resistor to remove, I just created a solder bridge across the two contacts. Ideally gridseed would have added a header post here, like they did with vid0.
Could this be done via graphite pencil mod?
Possibly, though the pencil mod will decrease resistance, whereas we want the opposite (on the particular resistors I'm looking at). It might be possible to target a different resistor. What this mod is doing is setting vid1 = 1 (solder part) and vid0 = 1 (voltage=1 part). Vid0 and vid1 are connected to a 2-bit VID buck converter, which selects between four output lines (set0, set1, set2, set3). On my miners, the resistance of the resistors connected to these lines are 33, 30, 27, and 36 K (this is different than gridseed's PCB spec!). By default vid0 = 0 and vid1 = 0, so you get 33 K. I experimented with all four vid0/vid1 values and found that power usage (and thus core voltage) is proportional to resistance.
https://github.com/gridseed/usb-miner/blob/master/hardware/GC3355%20USB%20for%20release.pdf?raw=true
| vid0 | vid1 | W | R (K) |
| 0 | 0 | 12.4 | 33 |
| 0 | 1 | 10.4 | 30 |
| 1 | 0 | 11.2 | 27 |
| 1 | 1 | 14.0 | 36 |
Could this be done via graphite pencil mod?
wow nice... At 950, what does it hash at? 400 kh/s?
Running stable?
Running stable?
Around 403 kh/s. I let it run for about 8 hours and no hardware errors. Trying 1000 MHz (424 kh/s) now. The solder bridge was a PITA, though I think I've got the technique down and will mod the remaining 11 units I have soon.
EDIT: 1000 MHz produces hardware errors, 975 MHz seems stable.
wow nice... At 950, what does it hash at? 400 kh/s?
Running stable?
So just bridge the section you circled? is there a resistor in place you have to remove?
Running stable?
So just bridge the section you circled? is there a resistor in place you have to remove?
DO THIS AT YOUR OWN RISK! I AM NOT RESPONSIBLE IF YOU BREAK YOUR MINER! THIS WILL VOID YOUR WARRANTY!
If you are feeling brave, there's a small modification you can make to your miner to increase the voltage a bit, which will let you run at a higher voltage. First, you will need to perform a bridge solder (soldering a jumper might also be doable, though I did not yet try that). Second, you need to use my modified cgminer (https://github.com/dtbartle/cgminer-gc3355) and set voltage=1 in the gridseed-options part of your config. I've been able to run at 950 MHz without hardware errors. This will cause the miner to use an additional 1.6 W of power.
If you are feeling brave, there's a small modification you can make to your miner to increase the voltage a bit, which will let you run at a higher voltage. First, you will need to perform a bridge solder (soldering a jumper might also be doable, though I did not yet try that). Second, you need to use my modified cgminer (https://github.com/dtbartle/cgminer-gc3355) and set voltage=1 in the gridseed-options part of your config. I've been able to run at 950 MHz without hardware errors. This will cause the miner to use an additional 1.6 W of power.
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