Antminer S7 Will not mine

[macjax]

Ok guys. I figured out what was wrong and I wanted to post what the issue was for anybody else experiencing the same symptoms. It turned out I have a bad hash board. Only one is bad. I removed the boards one by one until the miner was up and running. I am very disappointed however because I have 2 practically brand new miners and each have a bad hash board. I spent hundreds of dollars on these and only got a full week or 2 of mining and now I need to purchase new hash boards because I doubt Bitmain will cover them as I didn't purchase them from their website. I still would like to know why this happened and what's to prevent it from happening again ? Like I said earlier, I have S3, S4, S5 and even S7-LNs miners and never had to replace one single hash board from years of mining. If the S9 units are like this then I will stay away from them as well. I hope Bitmain can see that I obviously have a defective batch as nobody else had issue like this..

Thanks guys for all your help !!!!!

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[NotFuzzyWarm]

Considering that the s7's have been out of production since shortly after the s9's arrived in spring there is no way that Bitmain would cover it as a warranty issue. Even if bought new from them back then and never used, warranty is only 90-days from you or the original buyer getting it.

My guess is that the bad boards have damage to the 3.3v feed to the PIC and GPIO circuits of the BB. Because all 3 boards get the 3.3v from the same point on the controller If 1 board is shorted it will try to take down the other boards as well.

Let me guess, the boards in each s7's were fed from 2 PSU's? That is when something like this is most likely to happen. When using 2 PSU's always be sure to power the controller last so the 3.3v comes alive after the +12v to all hash boards does.

[SEGMining]

Did you try moving them back to the outlet where they did work and see if they work again?

The initial description does not scream bad hash board to me, it makes me think that the outlet that you moved them to has bad wiring and is not supplying the power needed to the PSUs.

[macjax]

Considering that the s7's have been out of production since shortly after the s9's arrived in spring there is no way that Bitmain would cover it as a warranty issue. Even if bought new from them back then and never used, warranty is only 90-days from you or the original buyer getting it.

My guess is that the bad boards have damage to the 3.3v feed to the PIC and GPIO circuits of the BB. Because all 3 boards get the 3.3v from the same point on the controller If 1 board is shorted it will try to take down the other boards as well.

Let me guess, the boards in each s7's were fed from 2 PSU's? That is when something like this is most likely to happen. When using 2 PSU's always be sure to power the controller last so the 3.3v comes alive after the +12v to all hash boards does.

Yes, 2 power supplies powering up the S7. I always waited a few minutes before powering up the controller. I would power up the hash boards first. I always did this. Never once powered up everything at once. Even when I was using a single 1600 watt Bitmain power supply.

Is there anyway to fix these hash boards myself ? You are right about Bitmain not covering it. I just don't want to spend the $ on repairs and have the exact same thing happen to me again.

Thanks !!

[NotFuzzyWarm]

You really need to ask Sidehack about what might be damaged. He did a lot of poking around the s7 while figuring out the undervolting mod he came up with. I assume that if you swap data cable to move the bad board to a previously working port (and good board to port that had bad board) the problem follows the bad board?

As for powering up with a single supply as long as the supply has a single 12v rail - like the Bitmain ones do - by all means do it all at once using the supplies DC on-off jumper. Takes the whole sequencing thing out of the picture. It is supplies that have multiple 12v rails that can be a problem. For those be sure to not have different rails feeding the same board.

[macjax]

You really need to ask Sidehack about what might be damaged. He did a lot of poking around the s7 while figuring out the undervolting mod he came up with. I assume that if you swap data cable to move the bad board to a previously working port (and good board to port that had bad board) the problem follows the bad board?

As for powering up with a single supply as long as the supply has a single 12v rail - like the Bitmain ones do - by all means do it all at once using the supplies DC on-off jumper. Takes the whole sequencing thing out of the picture. It is supplies that have multiple 12v rails that can be a problem. For those be sure to not have different rails feeding the same board.

Thank you NotFuzzyWarm ! I am keeping away from the multiple power supplies and sticking with the single Bitmain 1600 PSU. What jumper are you referring to  ? I see a removable jumper on green and yellow wire. Is that the jumper ?

Thanks !!

[NotFuzzyWarm]

Yes. The yellow/green wires with green wire jumper is the DC output on/off control.

Assuming all PCIe leads are plugged in, best startup is:
Remove jumper (or if is replaced with a little switch like I do, open it)
Plug in psu.
Connect jumper/close switch. DC will turn on.

Using the jumper is best for on/off because it switches the DC output after the voltage is stable giving a very clean and solid on/off.

[macjax]

Awesome !! Thanks so much !