Volt modding Antminer S3+, I have a weird pcb(upgrade kit) and need help

[herpderp991]

Hey guys, trying to follow this post.  https://bitcointalk.org/index.php?topic=771979.msg11609261#msg11609261

Issue is, I can't find that resistor as I seem to have a weird PCB on my S3+.  I think it's an upgrade kit.

Any idea on which resistor to mod?

Here's an album with the pics.

https://imgur.com/a/VAVB9

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[adaseb]

Holy didnt think people still use Antminer S3.

I had the same issue as you, it was a differerent PCB and I had to pencil a different resistor. Try to search the old Antminer S3 topic and there should be photos there that I posted. I remember the resistor was very sensitive, and it took many tries to get the Ohm correct.

I think I am running it at 400Ghs @ 300Watts.

[herpderp991]

Found it here for anyone who is looking.

https://bitcointalk.org/index.php?topic=699064.760

So, R55 eh?  What kind of resistance should I expect and do I need to add more, or reduce it to adjust the voltage down?  I'm seeing 48.6Kohm.

[HerbPean]

Found it here for anyone who is looking.

https://bitcointalk.org/index.php?topic=699064.760

So, R55 eh?  What kind of resistance should I expect and do I need to add more, or reduce it to adjust the voltage down?  I'm seeing 48.6Kohm.

I would use a Potentiometer and play with it, monitor the voltage. I think you should stay in the range of 0.9v-1.1v at first, just to be safe. I'm use to play with the S1 board but never tried with the S3. the S1 had 4 chains of chips, so you needed 4 Pot / resistance per board.

There is all the clock and timing to be found with the voltage you want to use, that is the hardest part.



Found this ...

 Typical hash rate and power
Voltage(V) HashRate(GH/s) Current(A) Total power(W)  W/GH
0.72          14.18                10.40          7.49                0.528
0.75          15.75                12.24          9.18                0.583
0.80          17.33                15.20          12.16              0.702
0.85          17.33                20.00          17.00              0.981

EDIT: Check that => https://bitcointalk.org/index.php?topic=771979.60

EDIT2: It looks like the Resistance to be change is R17 ... and it's 8 per board not 4 like the S1

R17 & R20 are not in parallel. R17 goes from the Buck Converter Output voltage to the VFB input. R20 goes from the VFB input to ground. R17 is the one to adjust or change.

Also remember you need to make the same change on the other 7 resistors on the other Buck Converters, then repeat for the second board.

Rich

[herpderp991]

Don't lower resistance on R55.  I lowered it from 48k down to ~35k, power went from 300watts to 600watts.

How would I read the voltage?  I know where the ground point is.

Found it here for anyone who is looking.

https://bitcointalk.org/index.php?topic=699064.760

So, R55 eh?  What kind of resistance should I expect and do I need to add more, or reduce it to adjust the voltage down?  I'm seeing 48.6Kohm.

I would use a Potentiometer and play with it, monitor the voltage. I think you should stay in the range of 0.9v-1.1v at first, just to be safe. I'm use to play with the S1 board but never tried with the S3. the S1 had 4 chains of chips, so you needed 4 Pot / resistance per board.

There is all the clock and timing to be found with the voltage you want to use, that is the hardest part.



Found this ...

 Typical hash rate and power
Voltage(V) HashRate(GH/s) Current(A) Total power(W)  W/GH
0.72          14.18                10.40          7.49                0.528
0.75          15.75                12.24          9.18                0.583
0.80          17.33                15.20          12.16              0.702
0.85          17.33                20.00          17.00              0.981

EDIT: Check that => https://bitcointalk.org/index.php?topic=771979.60

EDIT2: It looks like the Resistance to be change is R17 ... and it's 8 per board not 4 like the S1

R17 & R20 are not in parallel. R17 goes from the Buck Converter Output voltage to the VFB input. R20 goes from the VFB input to ground. R17 is the one to adjust or change.

Also remember you need to make the same change on the other 7 resistors on the other Buck Converters, then repeat for the second board.

Rich

R17 is the one for the regular board, not the upgrade kit.

[adaseb]

The resistors and resistor values are different between those two PCBs. I had a few of the older S3 and they were easier to mod because you just had to pencil in 50% of its current Ohm. But the later ones had higher values and you had to pencil in a smaller amount and took alot of play and plug. You need to pencil it in, measure with Ohm meter and plug it in and measure the voltage. Was a big pain.

But you can use regular computer case fans and its CRAZY SILENT at 400Gh/s using 300 Watts. So a good heater.

[herpderp991]

The resistors and resistor values are different between those two PCBs. I had a few of the older S3 and they were easier to mod because you just had to pencil in 50% of its current Ohm. But the later ones had higher values and you had to pencil in a smaller amount and took alot of play and plug. You need to pencil it in, measure with Ohm meter and plug it in and measure the voltage. Was a big pain.

But you can use regular computer case fans and its CRAZY SILENT at 400Gh/s using 300 Watts. So a good heater.

How do I measure the voltage?

[SEGMining]

How do I measure the voltage?

with a multimeter.

Search for the S1 thread on this topic, I think it's by mstrongbow, there is a video on youtube by him as well that shows how to check it.

https://youtu.be/3COZ5LR0t5Q