BTCMiner - Open Source Bitcoin Miner for ZTEX FPGA Boards, 215 MH/s on LX150 - page 26.

tnkflx

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Quote from: ztex on December 01, 2011, 04:45:22 AM

Quote from: gusti on November 30, 2011, 08:43:50 PM

I highly recommend not buying anything from this vendor, his warranty is inexistant.

...

Gusti, In your mail from Nov 10 you wrote that smoke came out of one of the part. Why you destroyed the second board in the same way instead of asking me what is going wrong?

...

Powering the 2nd board after noticing smoke on the first one is kinda stupid...

ztex

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Quote from: gusti on November 30, 2011, 08:43:50 PM

I highly recommend not buying anything from this vendor, his warranty is inexistant.

Gusti returned two boards 2 days ago. Both voltage regulators on both boards where destroyed. These voltage regulators are over current and temperature protected. The only way do destroy voltage regulators is by over voltage.

Since the valid range of is clearly specified on the products page (http://www.ztex.de/usb-fpga-1/usb-fpga-1.15x.e.html#con5), this is not covered by warranty.

Here is an image which shows the 3.3V regulator of one of Gustis board:

Gusti, In your mail from Nov 10 you wrote that smoke came out of one of the part. Why you destroyed the second board in the same way instead of asking me what is going wrong?

These regulator circuits are used in 4 other products. I sold a few hundreds of them. Gusti is the only customer I know who destroyed this way regulators.

BTW, I just counted it: wrote Gusti 22 support mail which was not always easy. His last mail was

Quote

no problem, bro
I will make sure you will not sell a single card in the forum anymore

DeathAndTaxes

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Gerald Davis

Quote from: gusti on November 30, 2011, 10:20:43 PM

Quote from: Turbor on November 30, 2011, 10:17:27 PM

Perhaps we should wait what ztex has to say. So far you fucked up two boards. That's all we know for now.

I highly recommend TO BUY from this vendor as you can talk with him if there is a problem !

Sure I emailed all day long with Stefan today, he will not do anything to give a solution.
If you dare to take the risk, go ahead and buy from ZTEX, but the boards have NO WARRANTY and NO REFUND POLICY.

Most warranties don't cover damage from improper usage.

gusti

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Quote from: Turbor on November 30, 2011, 10:17:27 PM

Perhaps we should wait what ztex has to say. So far you fucked up two boards. That's all we know for now.

I highly recommend TO BUY from this vendor as you can talk with him if there is a problem !

Sure I emailed all day long with Stefan today, he will not do anything to give a solution.
If you dare to take the risk, go ahead and buy from ZTEX, but the boards have NO WARRANTY and NO REFUND POLICY.

Turbor

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BitMinter

Perhaps we should wait what ztex has to say. So far you fucked up two boards. That's all we know for now.

I highly recommend TO BUY from this vendor as you can talk with him if there is a problem !

gusti

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I highly recommend not buying anything from this vendor, his warranty is inexistant.

Turbor

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BitMinter

Quote from: DeathAndTaxes on November 29, 2011, 03:39:38 PM

Guess that was more a case of the pad sucking then the grease being super good.

Exactly

DeathAndTaxes

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Gerald Davis

Quote from: ztex on November 29, 2011, 03:10:51 PM

Remember it is not a 140W CPU. Any thermal grease can be used. Thermal grease is included in the heat sink kit delivered with the board.

Good point.

Just wondered because the cooling improved so much. Guess that was more a case of the pad sucking then the grease being super good.

ztex

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Quote from: DeathAndTaxes on November 28, 2011, 06:58:39 PM

Quote from: Turbor on November 28, 2011, 02:03:21 PM

Thanks for clarification. It is as you said. The thermal pad is sh!t !!! Angry

. Please tell your customers not to use it. I put some termal grease on and now it works at 192 MHz with max 0.68 % errorRate so far.

Good to know. What brand thermal grease did you use?

Remember it is not a 140W CPU. Any thermal grease can be used. Thermal grease is included in the heat sink kit delivered with the board.

I dissected the pad today. It is some kind of textile with sticky grey stuff and it quite thick. IMHO it is not usable for anything.

Turbor

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Quote from: DeathAndTaxes on November 28, 2011, 06:58:39 PM

Good to know. What brand thermal grease did you use?

I have a spare Scythe Katana 3 CPU cooler. First the idea was to replace the heatsink with the Katana but that would have been a massive overkill in almost every way. The grease (Scythe) seems to work fine. I never did that before and was a bit afraid to f.ck up the board but it's really a nice piece of hardware. The stock heatsink pad is just too thick imo.

DeathAndTaxes

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Gerald Davis

Quote from: Turbor on November 28, 2011, 02:03:21 PM

Thanks for clarification. It is as you said. The thermal pad is sh!t !!! Angry

. Please tell your customers not to use it. I put some termal grease on and now it works at 192 MHz with max 0.68 % errorRate so far.

Good to know. What brand thermal grease did you use?

Turbor

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Thanks for clarification. It is as you said. The thermal pad is sh!t !!! Angry

. Please tell your customers not to use it. I put some termal grease on and now it works at 192 MHz with max 0.68 % errorRate so far.

F.cked up one heatsink holder but i was able to replace it with a M3 screw. I could not be happier. Great product Cheesy

!

Quote from: ztex on November 28, 2011, 07:16:59 AM

Quote from: Turbor on November 26, 2011, 04:39:56 PM

Edit: Here is a screen when i start the miner. Why does it set the initial frequency to 184 MHz in my case and 200 MHz for someone else ? The board was running more than a week when i took that pic. Not that i want to complain ! I'm just trying to understand Wink

...

The software always starts with 184 Mz.

Your board seems to hold 192 MHz for about 20s. Since the error rate increases very quickly at maximum frequency it should do 184MHz with (almost) no errors (<0.1%).

If the error rate increases over time (0.3% as you wrote in a previous possting) this indicates a cooling problem.

ztex

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Quote from: Turbor on November 26, 2011, 04:39:56 PM

Edit: Here is a screen when i start the miner. Why does it set the initial frequency to 184 MHz in my case and 200 MHz for someone else ? The board was running more than a week when i took that pic. Not that i want to complain ! I'm just trying to understand Wink

...

The software always starts with 184 Mz.

Your board seems to hold 192 MHz for about 20s. Since the error rate increases very quickly at maximum frequency it should do 184MHz with (almost) no errors (<0.1%).

If the error rate increases over time (0.3% as you wrote in a previous possting) this indicates a cooling problem.

Turbor

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Tnx for the information. I'll check this. But as long as it runs at 184 with no error there is nothing to fear right ?

Edit: Here is a screen when i start the miner. Why does it set the initial frequency to 184 MHz in my case and 200 MHz for someone else ? The board was running more than a week when i took that pic. Not that i want to complain ! I'm just trying to understand Wink

...

ztex

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Quote from: Turbor on November 26, 2011, 03:38:07 PM

I went with the thermal pad that came with the heatsink.

I never tried out this thing. Check the temperature of the (bottom side) of the PCB below the FPGA. If it feels quite warm after a runtime of at least 30min
the heat conductivity of the pad is to bad.

Quote

There is no problem for me with 180 mh/s 24h. Just interesting to see that others run other frequencies. I have almost zero error rate. Will the device only clock (up) at startup ?

The boards are clocked up at start-up until the effective hash rate decreases and then are clocked down by one step. Since the maximum error rate is used for frequency optimization the boards usually hold this frequency. BTW, nextMaxErrorRate denotes the maximum error rate of the next frequency step.

If your board holds the 192 MHz for more the a few seconds and then clocks down to 184 MHz at an error rate of 0.3% this indicates a cooling problem.

ztex

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Quote from: sadpandatech on November 26, 2011, 01:46:56 PM

Your's sounds more what I would expect from the latest production he has out. I am wondering, do you guys know what voltage your units are? I.E. what resistance is on R12/R13?

All boards that were delivered out have a core voltage of 1.23V. The first lot with 1.25V (2% to 3% faster) will be produced end of December.

ztex

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Quote from: sadpandatech on November 26, 2011, 11:57:23 AM

If I understand his software correctly, it automaticly adjusts the freq up/down based on the error rate.

With that in mind if we 'force' the unit to 200MHz and it is getting a theoretical 10% error rate the hash rate would still be 180MHs. It would be nice to have the option to manually adjust the error tolerance though to set the optimum limit of error/freq ourselves.

The software automatically chooses the frequency which delivers the highest effective hash rate. This calculation is based on the maximum error rate (maxErroRate) in the output.

A better optimization goal would be maximize the income based on error rates and considering the energy costs. But we are talking about average improvements of fee per mill ...

Turbor

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I went with the thermal pad that came with the heatsink. The heatsink gets a bit warm but not hot. There is no problem for me with 180 mh/s 24h. Just interesting to see that others run other frequencies. I have almost zero error rate. Will the device only clock (up) at startup ?

ztex

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Quote from: Turbor on November 26, 2011, 12:06:18 PM

I have an extra 92mm fan blowing at the board. Your right about self adjustment. It changes to 192 MHz on startup but then always goes back to 184 MHz. At 184 the error rate is below 0.3 %.

The minimum guaranteed hash rate is 176 MH/s. But in fact I never saw a 1.15x board which is as slow as yours.

If your board can only do 184 MHz at an error rate of 0.3% it will hold the 192 MHz only for a few seconds. If your board holds it longer you have a cooling problem.

First check the heat sink. If it feels hot their is not enough airflow. Then check the temperature of the PCB below the FPGA. If it feels warm there is an air gap between heat sink and FPGA. More thermal grease should solve this problem

Turbor

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Can this be a thermal thing ? I placed the heatsink myself. Should be perfect. I'm happy so far with the board.

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