Antminer s7 hash board that don't hash.

[SA007]

I have 6 antminer S7's and some have a very low hashing rate, only one of 3 boards is hashing.

The strange thing is that I can't find anything wrong, the boards are detected, they have a normal temperature, no x's in the asic's but no hashing at all.
I did a firmware upgrade (even though they are at the newest firmware) but that did not help.

I don't know which batch they are (second hand).
I have 4 board with the same problem:
2 boards with 30 asic's
2 boards with 54 asic's (one shows temperature as 0).

Connecting them on different controllers or power supplies or lowering the frequency doesn't seem to help.
The 30-asic boards have electrolytic capacitors, they are fine (ESR and capacitance is normal)

I have a fully kitted out electronics lab if that helps.

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[fanatic26]

FYI - there are no 30 asic boards. There are only 45 and 54 chip boards, if you are seeing a 30 chip board that means it is a malfunctioning board.

[SA007]

That is good to know.

The two boards that give 30 asics I just didn't count them and assumed the count in the web interface was correct.
But indeed they have more asic's.

I'm currently focussing on the 2 54 asic boards that i have here (the others are still in my farm), what is see in the interface is this:
http://bitcoin.sa007.nl/brokenornot.png

It has only been running 3 minutes here, but also at 30 minutes it doesn't display any x's.

In case it helps, I have run dmesg via ssh, it is filled with lines like:

Code:

[  111.392938] ch5-as42: dev->task_buffer_wr{0x00001ea0}rd{0x00000022}ret work_id{0x8000} don't match task_buffer_match{0x0000}
[  111.404733] asic cmd return c3ff09f0
[  111.408476] chain5 reg crc_r{0x16}crc{0x25} Err ret{0xc3ff09f0}

http://bitcoin.sa007.nl/dmesg

If I run the same controller with a working 54 asic board, that one stops giving those lines after about a minute and starts mining, the broken board don't seem to start or something.

I still don't have a clue what is happening here.