Avalon ASIC users thread

[thorvald]

first crash with firmware 703
I started with auto mode from 370
after a while it will go to 364-368 
after 20+ save+apply changes it will start normal and the hash will drom until 0 , all the diff1 shares went to Hw error
a cgminer stop start /restart will fix it for 30 min until it will go again down
it looks like a cgminer restart all the stats are 0 
changed to 325 + auto and is the same
soft reboot did not fix it
hard reboot is the way to go

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[el_rlee]

Can it be that --avalon-auto is only working with a reading for the fan rpm's? I use water cooling and have no fans...
Also is it possible that the setting for 16 miners instead of 24 is not working?

Last time i looked at your screen i found a huge amount of hw errors even at moderate frequencies,
i would try in simular case (if auto fails) to increment manually in 5 Mhz steps and look at hw error rate.
The only possible way fan data can make a "collision" with auto frequency option in this piece of code,

Code:

			if (!info->optimal) {
				if (info->fan_pwm >= opt_avalon_fan_max) {
					applog(LOG_WARNING,
					       "AVA%i: Above optimal temperature, throttling",
					       avalon->device_id);
					avalon_dec_freq(info);
				}

but info->fan_pwm is not rpm sensor reading, its pwm setting for fan speed. Even if you don't have one or
it just not connected - it will keep on passing pwm value to controller. So if your fan reading is zero -
there is no protection besides --avalon-cutoff option, its just for info purpose in current version.
Thats how i figured it out after looking at sources when my new fans went to 0 rpm and temperature starts growing.
I see no reason for changing 24 to 16 miners options to not work, only one thing - they must be plugged in DATA_P1 and P2 ports.

That was your message in my thread:

You should check accepted diff1 shares against hw errors, thats what you really want to know.
According to your screen you have ( 9032 / 735510 ) * 100% = 1.22% error rate
Try the latest firmware that was posted in "Avalon ASIC users thread" and overclock it to 375+

--avalon-auto seams working now, maybe I just was too impatient. I just don't get the results I wanted with my water cooling, frequency is on 354 now with the auto option. I am thinking of applying thermal paste to the back and an aluminum plate to the front which really presses the chips down onto the heatsink.

[BenTuras]

... and an aluminum plate to the front which really presses the chips down onto the heatsink.

It has been said many times not to put anything on top of the chips. You'll destroy them.

[el_rlee]

... and an aluminum plate to the front which really presses the chips down onto the heatsink.

It has been said many times not to put anything on top of the chips. You'll destroy them.

Thru cooling?!

[Tesla71]

Anybody mentioned the fact that the unit gets real hot at the bottom?
Any advise to make that better or doesn't that really matter? Maybe place it upside down ?

[SolarSilver]

Anybody mentioned the fact that the unit gets real hot at the bottom?
Any advise to make that better or doesn't that really matter? Maybe place it upside down ?

They get hot on the bottom because the hashing module is screwed to the heatsink and the heatsink is screwed to the bottom of the case. As the heatsink is not touching the top of the case, the top does not get hot.

The internal fans should do the job of keeping things cool, the bottom will not get hotter than the heatsink anyways

You can add additional air cooling externally on the case bottom if that makes you feel more comfortable.

Keep the case horizontally. I would not flip it upside down, that would make the hashing modules hang from the top, it was not designed for that.

[-ck]

Mine has been upside down most of the time without a problem. It all looked pretty well secured when I opened it up and heat radiates from the "base" when it's upside down.

[invader]

... and an aluminum plate to the front which really presses the chips down onto the heatsink.

It has been said many times not to put anything on top of the chips. You'll destroy them.

It was said because putting anything on chips would make air pass worse thru the aircooled unit and will decrease overall cooling efficiency. Also was noted that chips has bad thermal conductivity on top due to the air gap in chip package, so most of the heat is going to the bottom where is good thermal conductivity exist and then to pcb. But really, i think screws on PCB is just enough for purpose of "pressing to heatsink"

[el_rlee]

... and an aluminum plate to the front which really presses the chips down onto the heatsink.

It has been said many times not to put anything on top of the chips. You'll destroy them.

It was said because putting anything on chips would make air pass worse thru the aircooled unit and will decrease overall cooling efficiency. Also was noted that chips has bad thermal conductivity on top due to the air gap in chip package, so most of the heat is going to the bottom where is good thermal conductivity exist and then to pcb.

I was thinking about reworking the original heatsinks to fit on the top...

[invader]

I was thinking about reworking the original heatsinks to fit on the top...

It's useless in general, too much work for too little effort. Better pay more attention to thermal contact of PCB bottom and heatsink. Also thanks for pictures, i noticed your chips is at 50 c, thats a good temperature - they will work fine up to 100c as was said somewhere. At least in datasheet i see operating temperature range [ -20 .. +85 ]

[-ck]

--avalon-auto seams working now, maybe I just was too impatient. I just don't get the results I wanted with my water cooling, frequency is on 354 now with the auto option. I am thinking of applying thermal paste to the back and an aluminum plate to the front which really presses the chips down onto the heatsink.

Heat's not the rate limiting thing for frequency it seems. In cold weather mine isn't getting hot but I can't get it up much past 355. The chips probably need a voltage mod to run at higher frequencies than that, but at least you've sorted out the heat side.

[BenTuras]

Mine has been upside down most of the time without a problem. It all looked pretty well secured when I opened it up and heat radiates from the "base" when it's upside down.

If it's a silver unit I wouldn't put it upside down. Just have a look at the few number of threads of the screws that hold the heavy boards to the case: https://bitcointalk.org/index.php?topic=211928

If it's a black unit, I have seen messages that this issue has been solved.

[el_rlee]

I was thinking about reworking the original heatsinks to fit on the top...

It's useless in general, too much work for too little effort. Better pay more attention to thermal contact of PCB bottom and heatsink. Also thanks for pictures, i noticed your chips is at 50 c, thats a good temperature - they will work fine up to 100c as was said somewhere. At least in datasheet i see operating temperature range [ -20 .. +85 ]

The plate would only be for better thermal contact of PCB bottom and heatsink. The PCB is just too soft to be pressed against the aluminium properly over the whole surface just by the few screws.

What would it take for a volt mod? Soldering around on every single step down converter?

How far (in % of HW errors) can I go up with the frequency without risking of damaging something? What's the time frame the --avalon-auto option uses to calculate the HW error rate and adjust the frequency?
 

[rudrigorc2]

fans are almost at max..... but tempratures look low wnough

what's the max, 4000?

One machine here both coolers runs close to 4000, 39xx 
and the other one has one fan that max out at 3720

[invader]

What would it take for a volt mod? Soldering around on every single step down converter?

Yes, you need to change R9 resistor value in step-down converter, according to datasheet on TPS40193
the formula is

R9 = ( Vfb * R10 ) / ( Vout - Vfb ) , where Vfb is constant = 0.591v , R10 = 10.5k

for example, calculation for Vout = 1.2 give

R9 = ( 0.591 * 10500 ) / ( 1.2 - 0.591 ) = 6205.5 / 0.609 = 10189 , 10k resistor

in datasheet maximum Vout = 1.32

R9 = ( 0.591 * 10500 ) / ( 1.32 - 0.591 ) = 6205.5 / 0.729 = 8512 , 8.5k resistor

To make ~ 8.5k resistor from 10k you need to add in parellel 60k resistor, but i would advice you try to increase voltage in a little steps like 0.01v before you reach 1.32v and look at hw error rate.

Sorry but i cant point you now where is that resistor located, i just look at hash_unit schematics.

How far (in % of HW errors) can I go up with the frequency without risking of damaging something?

I think hw error rate 2-3% is the highest that you want to see, more than that is a waste of energy.
You can damage the chips by increasing voltage to more than 1.32v - be careful.

[el_rlee]

At least in datasheet i see operating temperature range [ -20 .. +85 ]

Are you sure that's not Tj?

[loshia]

What would it take for a volt mod? Soldering around on every single step down converter?

Yes, you need to change R9 resistor value in step-down converter, according to datasheet on TPS40193
the formula is

R9 = ( Vfb * R10 ) / ( Vout - Vfb ) , where Vfb is constant = 0.591v , R10 = 10.5k

for example, calculation for Vout = 1.2 give

R9 = ( 0.591 * 10500 ) / ( 1.2 - 0.591 ) = 6205.5 / 0.609 = 10189 , 10k resistor

in datasheet maximum Vout = 1.32

R9 = ( 0.591 * 10500 ) / ( 1.32 - 0.591 ) = 6205.5 / 0.729 = 8512 , 8.5k resistor

To make ~ 8.5k resistor from 10k you need to add in parellel 60k resistor, but i would advice you try to increase voltage in a little steps like 0.01v before you reach 1.32v

Sorry but i cant point you now where is that resistor located, i just look at hash_unit schematics.

How far (in % of HW errors) can I go up with the frequency without risking of damaging something?

I think hw error rate 2-3% is the highest that you want to see, more than that is a waste of energy.
You can damage the chips by increasing voltage to more than 1.32v - be careful.

invader ,

Nice reading thank you  

What about TPS40193? it was rated at 20A max. Will it burn into flames? At 350 each chip according to rumors (calcs on PSU input - Wall) eats about 1.8-1.9 A

What about other elements inductors and such?

Thank you in advance

[el_rlee]

I found the R9, unnecessary to mention that it is fucking small 

I guess it doesn't pay of to tweak around with the voltage, don't think that anybody will on existing boards.

[crazyearner]

Any ways on reducing hw errors and also  how to update to latest cgminer or use cgminer separate to one in config of Avalon ?

[Tesla71]

I noticed that the numbers of Fan# and Temp# are interchanged. Temp3 is alwas a bit more than Temp2, though Fan2 runs faster than Fan3.

Is that only how it is shown or maybe the fans are connected to the wrong output ? How to find out ?