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Author Topic: Cheap and simple repair of S7 hash board  (Read 13455 times)
Dragonizer
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March 21, 2017, 02:35:26 AM
 #121

second board is fixed , i have it running at 500 freq/1.2 th , dont have my volt meter to set the voltage to run it at 700, so ill take care of that later tonight.

this isnt an easy fix by any means soldering to r17 is a royal pain , c76 isnt to bad but id imagine u could just solder to gnd on the pcie plug instead of the side of c76. that would make it a lil easier

that being said im sending the remainder of my boards to sidehack for pic replacement , instead of soldering the rest myself

http://i.imgur.com/PDfoefm.png

Who are 'sidehack' mate ?

Are they better then an RMA to Btmain ?

Thanks
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andresrp
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March 21, 2017, 04:04:50 AM
 #122

Hi, any repair guides for S7 boards showing the #48 asics? If im not wrong we have only the 54 chip version of the board. Thank you
Dibblah
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March 21, 2017, 07:57:59 AM
 #123

np, easy to mis-read.
Of course from a repair standpoint, that makes pulling chips a royal PITA. Thass why Sidehack has no interest in doing a stick using the s7/s9 chips.

It's not _that_ bad. As long as it's up to solder melting temperature, the black stuff is soft enough. Problem is, at that temp I think the package has started to weaken a little too. And you need some way to remove the black stuff from each chip which is... Less than fun. That combined with the pin-pitch makes this definitely not a hobby job.

Cheers,

Allan.
Dibblah
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March 21, 2017, 08:16:43 AM
 #124

Hi, any repair guides for S7 boards showing the #48 asics? If im not wrong we have only the 54 chip version of the board. Thank you

There is essentially not a lot you can do without QFN rework facilities and understanding the board. If it's a chip fallen off situation (desoldered), you may be able to get away with a DIY fix, but even then it's not easy. Likely faults in high-temp environments on the 54 chip boards from what I've heard are:
 Cap failure - which is not impossible to fix, the heatsinks on the back come off fairly easily.
 Failure of the tiny boost converter which does the I/O voltages for the last (couple?) of sets of chips. Hard to fix unless you know what you're doing.
 Failure of an ASIC (solder joint issue). Possible to flux and reflow, but cleaning without softening the adhesive holding all the rest of the heatsinks on is not fun.
 Failure of an actual ASIC chip. Find the chip and replace. Not going to happen if you don't already do fine-pitch SMD work.

There is no PIC or voltage control on a 54 chip board.

I haven't seen a 54 chip board with black adhesive, but I don't have a large sample size.

You can get some diagnostic information by reading the voltages between each "set of 3" heatsinks - there should be around .666 volts per chip (some small amounts of variance is normal). However, even then, there's not a lot you can do without SMD rework.

Check the kernel log - I would expect to see timeouts because it can't see any of the chain - hence why it's defaulting to 48 or 30 chips.

Dragonizer
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March 21, 2017, 12:33:05 PM
 #125

Hi guys,

How do i check that the pic is faulty, at what to points do you test ?

Is it a resistance test or do you power board and test the voltage ??

ANY help much appreciated

Thanks
NotFuzzyWarm
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March 21, 2017, 12:49:53 PM
 #126

Hi guys,

How do i check that the pic is faulty, at what to points do you test ?
Is it a resistance test or do you power board and test the voltage ??
ANY help much appreciated
Thanks
You may want to look at Sidehack's Modding s7 thread https://bitcointalk.org/index.php?topic=1504228.msg15360994#msg15360994
Lots of good info in there including how to change Vcore with a simple firmware mod.

-Joshua Zipkin aka Joshua Alexander leaked AMT A1 miner skype chats http://bit.ly/1Qjt6lj
-For bitcoin to succeed the community must police itself.
-Support Sidehacks miner development. Donations to:   1BURGERAXHH6Yi6LRybRJK7ybEm5m5HwTr
Dragonizer
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March 22, 2017, 07:27:16 PM
 #127

Hi guys,

How do i check that the pic is faulty, at what to points do you test ?
Is it a resistance test or do you power board and test the voltage ??
ANY help much appreciated
Thanks
You may want to look at Sidehack's Modding s7 thread https://bitcointalk.org/index.php?topic=1504228.msg15360994#msg15360994
Lots of good info in there including how to change Vcore with a simple firmware mod.

I thought that was the inductor (copper coil with magnet in middle) and the PIC is lower down to the left ?


http://i65.tinypic.com/1zfh8r9.jpg
NotFuzzyWarm
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March 22, 2017, 11:40:58 PM
 #128

Hi guys,

How do i check that the pic is faulty, at what to points do you test ?
Is it a resistance test or do you power board and test the voltage ??
ANY help much appreciated
Thanks
You may want to look at Sidehack's Modding s7 thread https://bitcointalk.org/index.php?topic=1504228.msg15360994#msg15360994
Lots of good info in there including how to change Vcore with a simple firmware mod.
I thought that was the inductor (copper coil with magnet in middle) and the PIC is lower down to the left ?

Ref your pic, is not a magnet, is a ferrite core for the inductor. The regulators run around 50-100kHz and iron laminations are useless at those freq.

I believe the PIC is on the other side of the board off to the right of 3 other larger chips. Follow the traces from the 6-pin programming connection. I have a s7 board pulled and will take it into work tomorrow to look at the actual chip numbers with a microscope. DAMN that writing is tiny .

EDIT: Just looked at the chips under a video scope and you are right. That little chip U3 on the inductor side of the board is the PIC.

-Joshua Zipkin aka Joshua Alexander leaked AMT A1 miner skype chats http://bit.ly/1Qjt6lj
-For bitcoin to succeed the community must police itself.
-Support Sidehacks miner development. Donations to:   1BURGERAXHH6Yi6LRybRJK7ybEm5m5HwTr
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