HELP - Any BITCOIN miners out there, i have 3 faulty Antminer S7 Hashboards, how can i test repair ?

Thread Starter

bilabonic

Joined Mar 12, 2017
4
Hi All

I have removed the three S7 boards and all 'look' ok, i have tried them in a good miner, but get the same result, all asic chips are fine, temps are fine but i do not get ny hashrate.

At this moment in time ONLY Bitmain.com (the main supplier) offers repairs only to the boards, with a super quick turn around and it is runoured to be a VERY simple fix, mine failed after one of the 2 fans (input/output) stopped and it overheated.
The first thing i looked at was the capacitors.

High temp 16v, 1000uF.
S7 Capacitor by Leighton Kappen, on Flickr

There is also a smaller cap above it but gtting schematic for the PCB is impossible !!!

I have 4 faulty boards each with 4 of these capacitors.

I have not got a dedicated capacitor tester, but using a Multimeter i get -

Capacitors 1,2,3 and 4 in same location on each board -

1- 33.8ohm, 33.7ohm, 2.2Mohm and falling, 1.4MO and falling.

2- 55.5, 55.9, 2.4MO and falling, 1.9MO and falling.

3- 60.8, 61.1, 2.3MO and falling, 1.95MO and falling

4- did not test as still in machine..

What do you reckon guys ??

I'm more of an industrial spark where we would just replace the board, no matter of cost....

Cheers
 

hp1729

Joined Nov 23, 2015
2,304
Hi All

I have removed the three S7 boards and all 'look' ok, i have tried them in a good miner, but get the same result, all asic chips are fine, temps are fine but i do not get ny hashrate.

At this moment in time ONLY Bitmain.com (the main supplier) offers repairs only to the boards, with a super quick turn around and it is runoured to be a VERY simple fix, mine failed after one of the 2 fans (input/output) stopped and it overheated.
The first thing i looked at was the capacitors.

High temp 16v, 1000uF.
S7 Capacitor by Leighton Kappen, on Flickr

There is also a smaller cap above it but gtting schematic for the PCB is impossible !!!

I have 4 faulty boards each with 4 of these capacitors.

I have not got a dedicated capacitor tester, but using a Multimeter i get -

Capacitors 1,2,3 and 4 in same location on each board -

1- 33.8ohm, 33.7ohm, 2.2Mohm and falling, 1.4MO and falling.

2- 55.5, 55.9, 2.4MO and falling, 1.9MO and falling.

3- 60.8, 61.1, 2.3MO and falling, 1.95MO and falling

4- did not test as still in machine..

What do you reckon guys ??

I'm more of an industrial spark where we would just replace the board, no matter of cost....

Cheers
https://bitcointalk.org/index.php?topic=1420909.0
 

Thread Starter

bilabonic

Joined Mar 12, 2017
4
I am blocked from site after being on there for YEARS because i forgot my password and tried memorable data to recover, got that wrong ,so it just comes with an email address, which i have emailed about 20 times a day to get back in, i desperately need to get back on there ?

Is there any way you could 'cache or copy the pages and email them to me ??

Cheers
 

Papabravo

Joined Feb 24, 2006
21,157
Without access to tools and information, your chances of repairing the boards is remote. Why do you think a reading in ohms has any bearing on the capacitor in question? What is the cost of replacing them?
 

Thread Starter

bilabonic

Joined Mar 12, 2017
4
Because that's the only thing i can check with my standard multi meter, i checked all the diodes and they seem fine, when i compared the caps in question, one the working boards they all had a high falling resistance, anyway i replaced all 4 with 1000uF, 25v and it works !!!!!

I have ordered a capacitor tester, but what else do i need for resistance, is there not a 'chart' that gives the rough value of what it should be ?

I work on 11kv/3.3Kv/415v/plc's etc.....so as i said we just replace a faulty board/card and bin it or send it away for repair in some cases.

But want to get into more of the 'repair' side of things if possible and this seemed a great site to start.....

Cheers guys, i appreciate your replies....
 
Last edited:

Papabravo

Joined Feb 24, 2006
21,157
Because that's the only thing i can check with my standard multi meter, i checked all the diodes and they seem fine, when i compared the caps in question, one the working boards they all had a high falling resistance, anyway i replaced all 4 with 1000uF, 25v and it works !!!!!

I have ordered a capacitor tester, but what else do i need for resistance, is there not a 'chart' that gives the rough value of what it should be ?

I work on 11kv/3.3Kv/415v/plc's etc.....so as i said we just replace a faulty board/card and bin it or send it away for repair in some cases.

Cheers guys, i appreciate your replies....
There is no relationship between capacitance and what you would measure with a DC ohmmeter. The reactance of a capacitor, measured in ohms, depends on frequency. At DC, or zero frequency, the reactance is infinite. You really need to get a grip on basic principles. Glad your replacement strategy worked.

https://en.wikipedia.org/wiki/Electrical_reactance
 

Thread Starter

bilabonic

Joined Mar 12, 2017
4
Cheers, i've done the theory about 20 years ago...lol, with advanced maths, imaginary numbers, etc.

Think i doe all of that in your link, but in HEAVY industry your dealing with motors/PLC's etc and not the actual electronics, we would have a dedicated tech for that.

XL=2 pie fl etc...lol Capacitive reactance, capactive resistance, lot of osc scope work, but NEVER had a use for it in heavy industry.

We even usd to test the caps, by freezing them and heating as i remember.

Looks like s GOOD place for help and advice anyway.

Cheers
 
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