GridSeed 5-chip USB miner voltage mod

[Andareed]

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.

[chanberg]

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?

[Andareed]

wow nice... At 950, what does it hash at? 400 kh/s?

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.

[sang]

Could this be done via graphite pencil mod?

[Andareed]

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

[Andareed]

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.

[sang]

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.

[Andareed]

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.

It was really annoying to do. What I did was get a gob onto the general bridge area, and then ran the solder tip (I have a fairly fine tip) along both sides of the bridge to collect any stray solder.

EDIT: Going to try using this to solder the bridge: http://www.ebay.com/itm/151169919397

[RowanX]

Andareed are you running with or without the fan @ 950?

[Andareed]

Andareed are you running with or without the fan @ 950?

Without. I have two rows of six units lying on their side, top to bottom, with a pair of 120mm fans blowing across them. I've only modded a single unit so far, though 10-15% more heat isn't something I'm going to worry about.

[worldlybedouin]

Wow!  This is cool!  I wish I had the skills to even contemplate such a delicate HW hack...alas, the last thing I tried to solder turned into a giant silver blob.

[Blueman666]

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.

It was really annoying to do. What I did was get a gob onto the general bridge area, and then ran the solder tip (I have a fairly fine tip) along both sides of the bridge to collect any stray solder.

EDIT: Going to try using this to solder the bridge: http://www.ebay.com/itm/151169919397

Nice work

Cant imagine that solder paint will help though. Try a piece of very thin fuse wire a couple of inches long so you can hold it easy. Tack it on to the 2 contacts then break off the excess by bending back and forth or use a small blade to cut it.

[Andareed]

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.

It was really annoying to do. What I did was get a gob onto the general bridge area, and then ran the solder tip (I have a fairly fine tip) along both sides of the bridge to collect any stray solder.

EDIT: Going to try using this to solder the bridge: http://www.ebay.com/itm/151169919397

Nice work

Cant imagine that solder paint will help though. Try a piece of very thin fuse wire a couple of inches long so you can hold it easy. Tack it on to the 2 contacts then break off the excess by bending back and forth or use a small blade to cut it.

Interesting idea, but where do you get fuse wire from? I wonder if folding a few layers of tin foil would work.

[SVK]

There are SMD jumpers available however I'm not sure how small jumper we would need. One test miner should be with me by thursday. I can't wait to test it out

[li_gangyi]

Conductive pens might be a viable option. Someone needs to try that out.

[Andareed]

There are SMD jumpers available however I'm not sure how small jumper we would need. One test miner should be with me by thursday. I can't wait to test it out

I can measure later today, but the're almost certainly 0.1"/2.54mm pitch. Something like this would work:
https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2076826&productId=2076826
https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=112432&productId=112432

[SVK]

There are SMD jumpers available however I'm not sure how small jumper we would need. One test miner should be with me by thursday. I can't wait to test it out

I can measure later today, but the're almost certainly 0.1"/2.54mm pitch. Something like this would work:
https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2076826&productId=2076826
https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=112432&productId=112432

Or http://www.digikey.com/product-detail/en/S1731-46R/952-1581-6-ND/2281857

[klintay]

Andareed you are such a dude! Thank you for this

[li_gangyi]

Andareed: did you measure the voltage output of the regulator to find out how much did this increase the voltage to? Just curious as to how much this mod changes the voltage.

[worldlybedouin]

@Andareed...I don't suppose you reside in the NYC metro area?  If you did, I'd love to just bring my miners over to you and pay you to do this hardware mod.