How often do you lose a hash board on your S9 ?

It does not seem uncommon for a single S9 board to go bad, either not showing at all , showing 0 asics or showing all 63 but hashing at 0th, I have recently started to face the issue more often than before , this only happened at like 1 to 20 ratio , but with the recent gears i got , the ratio is a bit more than that.

The strange thing is, it's never 2 boards , never 3 - it is always that one single board which to me usually the middle board.

I wonder what is the % or ratio of this happening to others? I have also noticed that this is more common on S9 than on the S9i versions.

Calling it "not uncommon to lose a hash board" is being too kind. I got fed up with losing s9 boards on an almost regular basis and a few years ago moved to Avalons because of BM's crappy designs. To date just 1 A7 bad hash board and zero A8 failures

That said, now that you mention it, yes: Was always just 1 board and generally the center one.

The middle chips of the first few columns of the center board get almost zero airflow because they're right in front of the fan motor. Temp sensors are probably wired in at the other end of the board and don't reflect this.

Quote from: sidehack on June 18, 2019, 03:54:08 PM

this is exactly why it happens.

I run a lot of s9's two board with a dead s9 board in the center. this works well.

Quote from: NotFuzzyWarm on June 18, 2019, 01:19:45 PM

Calling it "not uncommon to lose a hash board" is being too kind.

Ya i guess that was a terrible choice of words Grin

Quote from: sidehack on June 18, 2019, 03:54:08 PM

The middle chips of the first few columns of the center board get almost zero airflow because they're right in front of the fan motor. T

that is a sharp observation, regardless of how simple it sounds the average person (like me) can't figure that much.

so , is it safe to assume that the temps on the first a few chips towards the intake fan are always 5/10/15 degrees more than what the sensor read? is there anything to help cool that particular part?

Quote from: mikeywith on June 18, 2019, 08:33:47 PM

...
is there anything to help cool that particular part?

Well you can always mount the fans on some standoffs that are an inch or so long (and close up the gap between casing and fans of course).
That will give the airflow a chance to fill in the dead spot and also probably dramatically reduce the siren effect by moving the fan blades away from the heat sink fins.

Quote from: NotFuzzyWarm on June 18, 2019, 08:41:59 PM

That sounds like a good plan , but it's a lot of work , guess I will just leave them to face their destiny.

These gears will very soon be nothing but door holders anyway, even for someone with free (limited) power like myself, so I don't think I will be spending another penny on them.

I hope the design is different on all new gears, it would be stupid if they kept the same spacing and all for the new gears, I have not had the chance to really see how are the S15/S17's boards placed, but judging by the size of the miner's case, it seems like they have improved the cooling.

Going to a short wide board on the S15 was definitely an improvement. Anyone that ever ran Spondoolies rack gear understands exactly why. With long boards, the cooling air is already so hot by the time it reaches the last row of chips that it has very little effect. Short boards with short air paths don't heat the air as much so it cools the whole board better.

If you pull the boards out of an S9, you'll see the chipside heatsinks are missing on a wedge of chips at the fan end of the board. I assume that's to help open a void for air to come in from the periphery and cool the chips behind the motor. Not as effective as just, as Fuzzy recommended, adding a bit of actual gap behind the motor, but that's extra steps and a nickel off the profit margin. Who cares if it increases reliability; planned obsolescence is the name of the game so they have a vested interest in building gear that breaks.

Quote from: sidehack on June 18, 2019, 10:40:32 PM

Who cares if it increases reliability; planned obsolescence is the name of the game so they have a vested interest in building gear that breaks.

Exactly, these gears will be obsolete mostly before they wear out , i can understand why they are not putting too much effort in terms of increasing the lifespan of these gears.

after this topic I lost another middle board , for like a few hours, when i went to check , it suddenly came back online and still running fine, it was showing 0th but now shows the normal 4.xx th, I am facing more issues with the older version of S9s than that new once, the S9i seems to have a bigger frame than the S9 i think the first rows of the middle chip get slightly better cooling.

if you have old dead 120mm fans 25mm thick you can use them to space the fan.

that 1 inch or 25mm back space will help a lot.

Quote from: philipma1957 on June 19, 2019, 09:57:00 PM

Let me get this straight, so you suggesting double fan? But then the dead fan's motor will block the first chips still, also the dead fan will reduce the airflow coming in from the working one, things could get worse ,no?

You would remove the motor and fan blades from the dead fan.

In the old watercooling days, you would do that instead of buying a shroud to move fans back off heatcore type radiators. But then the radiator manufacterers started incorporating shrouds into their designs and using them with fans became unnecessary. Plus the fact they took up a lot more space.

Quote from: Biffa on June 21, 2019, 06:02:26 AM

You would remove the motor and fan blades from the dead fan.

Ok this does make perfect sense, not sure how hard/easy it is going to be to remove the blades and motor without breaking the frame, also it so happens that i seldom get any dead fans even though i run most of them at 90% , got to give credit to bitmain for putting in some quality fans.

Dremel is your friend Grin

Quote from: Biffa on June 21, 2019, 12:05:44 PM

I am a Makita person Grin

I will try to do it and post some pictures, i am not very good when it comes to dealing with tools, very impatient and usually break everything i try to fix.

You need dead fans? I got dead fans. Only takes a minute to bust the motors out of 'em.

Quote from: sidehack on June 21, 2019, 03:44:58 PM

You need dead fans? I got dead fans. Only takes a minute to bust the motors out of 'em.

I might need a few if I decide to take the route, will PM you if that happens, thanks a lot.

Quote from: philipma1957 on June 21, 2019, 07:14:23 PM

I really haven't had the time /mood to check how to bust those out, will do soon , I just hope I won't be needing any other tools other than the once I already have Grin

.

I want to try and keep this as cheap as possible for it to be worthy.

Let us know if you did a few.

I found a 7mm spacer on amazon works well.