i see the power board PDU is different than batch2 or 3 and i wonder if it is enough to power 4 modules.
Topic: Avalon ASIC users thread - page 97. (Read 438516 times)
does anyone use 4 modules with batch1 avalons?
i see the power board PDU is different than batch2 or 3 and i wonder if it is enough to power 4 modules.
i see the power board PDU is different than batch2 or 3 and i wonder if it is enough to power 4 modules.
If 50BTC is using a large coinbase, you might have been getting struck by the excessive CPU usage limitation in older firmware just like p2pool was. This might manifest as duplicate shares and only show up as rejects at your pool. Most of the recent updates were created to address precisely that problem. Try my latest firmware.
http://ck.kolivas.org/apps/cgminer/avalon/20130814/
Thank you, ckolivas. I'll consider to move to the new firmware as it gets mature. I just read the feedback that new FW are affected by the lower hashrate than 0703.http://ck.kolivas.org/apps/cgminer/avalon/20130814/
Actually I'm very happy with the 20130813 release and further, it's a lot more stable on 4 hash module Avalons.
Two of my machines always ended up hanging showing values '0' for hash rate, temperature and fan speed. I've always blamed this on the FPGA controler board in the past. All my other machines did not do this. Coincidence, the two problem machines were 4 module machines, the others have 3 modules.
I always had to cold restart them using the PDU and this made their average hash rate over a day much lower than sometimes a 3 module machine. Sometimes they would soft restart themselves but flipflop in and out of idling. Only cold restart really helps.
So far 4 or so days without any need for restart...
More testing is required before I draw conclusions but it seems the problem has been fixed.
Give the new release a try, the reported hash rate is cosmetic.
Moved from bitparking to 50btc and now I'm constantly getting a lot of Rejected shares at Diff8 
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Change your diff to 64 on 50btc under settings for miner is probs why you getting too many rejected shares.
Going from 8diff to 64diff simply means your Reject share variance increases.
Coz on average you find 1/8 of the rejected shares ... but they are worth 8 times as much each.
If 50BTC is using a large coinbase, you might have been getting struck by the excessive CPU usage limitation in older firmware just like p2pool was. This might manifest as duplicate shares and only show up as rejects at your pool. Most of the recent updates were created to address precisely that problem. Try my latest firmware.
http://ck.kolivas.org/apps/cgminer/avalon/20130814/
Moved from bitparking to 50btc and now I'm constantly getting a lot of Rejected shares at Diff8
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Change your diff to 64 on 50btc under settings for miner is probs why you getting too many rejected shares.
Going from 8diff to 64diff simply means your Reject share variance increases.
Coz on average you find 1/8 of the rejected shares ... but they are worth 8 times as much each.
Moved from bitparking to 50btc and now I'm constantly getting a lot of Rejected shares at Diff8
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Change your diff to 64 on 50btc under settings for miner is probs why you getting too many rejected shares.
Going from 8diff to 64diff simply means your Reject share variance increases.
Coz on average you find 1/8 of the rejected shares ... but they are worth 8 times as much each.
If 50BTC is using a large coinbase, you might have been getting struck by the excessive CPU usage limitation in older firmware just like p2pool was. This might manifest as duplicate shares and only show up as rejects at your pool. Most of the recent updates were created to address precisely that problem. Try my latest firmware.
http://ck.kolivas.org/apps/cgminer/avalon/20130814/
Moved from bitparking to 50btc and now I'm constantly getting a lot of Rejected shares at Diff8
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Change your diff to 64 on 50btc under settings for miner is probs why you getting too many rejected shares.
Going from 8diff to 64diff simply means your Reject share variance increases.
Coz on average you find 1/8 of the rejected shares ... but they are worth 8 times as much each.
It is Avalon clone based on B2 design that I build self.
Congrats! Quote
How about B3 machines that have changed design ? I see on one photos hash unit are probably grouped in 4 on one PCB and added thermal sensor on it.
My unit is a batch 3. It looks like we are seeing the exact same voltage drop.
Moved from bitparking to 50btc and now I'm constantly getting a lot of Rejected shares at Diff8
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Does anybody have fixed issue like this?
Edit: FW both 20130703 and 20130723
Change your diff to 64 on 50btc under settings for miner is probs why you getting too many rejected shares.
Thanks lastbit and GandalfG for the info. I have access to a nice 12ghz oscilloscope and will take noise and ripple measurements of the output of the VR and see if it gets unstable past 20a.
Just took some measurements. At the top of the board closest to the VR im seeing 1.2v at the bottom im seeing 1.15v! Im surprised to see so much of a drop! They must have cheeped out on the amount of copper on the board.
Just took some measurements. At the top of the board closest to the VR im seeing 1.2v at the bottom im seeing 1.15v! Im surprised to see so much of a drop! They must have cheeped out on the amount of copper on the board.
I measure my board with my 100MHz oscilloscope with 1.3V mod and did not see noise on power lines. I check it now after over 10 days mining.
About drop:
Standby: 1.298V
395MHz:
1.278 on coil VR and nearest capacitor
1.268 first two chip
1.228 last chip.
I solder silver-plated wire 0,8mm across one board and check how its help.
Have any amps / watts per board power measurement?
Also, was this a b2 or b3? Did they change anything on the b3 miner boards?
I did not measure amps. It is Avalon clone based on B2 design that I build self. Buy PCB and parts from Strombom.
Actually have only 50 chip and patiently wait for supply from Bitsyncom.
50mv drop is horrible!
adding a couple thick wires from the output of the VR to the last chips should help a lot. although the problem could be a return path issue. I dont have my unit in front of me at the moment. I assume the bottom layer is Ground and the top is VCC? There may be an issue with the ground vias/pins not being able to handle the current.
Yes that huge drops are very undesirable. As I stated I solder wire and make measure again. I'm a little surprised that the original B1/B2 have a similar problem.
How about B3 machines that have changed design ? I see on one photos hash unit are probably grouped in 4 on one PCB and added thermal sensor on it.
I measure my board with my 100MHz oscilloscope with 1.3V mod and did not see noise on power lines. I check it now after over 10 days mining.
About drop:
Standby: 1.298V
395MHz:
1.278 on coil VR and nearest capacitor
1.268 first two chip
1.228 last chip.
I solder silver-plated wire 0,8mm across one board and check how its help.
Thanks for the info. It looks like it's more work to do. Loosing 3% hashrate for voltage drops would be sad.
50mv drop is horrible!
adding a couple thick wires from the output of the VR to the last chips should help a lot. although the problem could be a return path issue. I dont have my unit in front of me at the moment. I assume the bottom layer is Ground and the top is VCC? There may be an issue with the ground vias/pins not being able to handle the current.
Thanks lastbit and GandalfG for the info. I have access to a nice 12ghz oscilloscope and will take noise and ripple measurements of the output of the VR and see if it gets unstable past 20a.
Just took some measurements. At the top of the board closest to the VR im seeing 1.2v at the bottom im seeing 1.15v! Im surprised to see so much of a drop! They must have cheeped out on the amount of copper on the board.
Just took some measurements. At the top of the board closest to the VR im seeing 1.2v at the bottom im seeing 1.15v! Im surprised to see so much of a drop! They must have cheeped out on the amount of copper on the board.
I measure my board with my 100MHz oscilloscope with 1.3V mod and did not see noise on power lines. I check it now after over 10 days mining.
About drop:
Standby: 1.298V
395MHz:
1.278 on coil VR and nearest capacitor
1.268 first two chip
1.228 last chip.
I solder silver-plated wire 0,8mm across one board and check how its help.
Have any amps / watts per board power measurement?
Also, was this a b2 or b3? Did they change anything on the b3 miner boards?
lastbit in terms of what your doing you might want to try this as modding not uploaded all details yet but this s on a batch 2 unit and working out the layout for batch 3 will have details on my website when I get around to it.
Thanks crazyearner. Indeed something along the lines of what you did. But batch#3 id different, each 2 modules are arranged in mirror with heatsinks facing one another. And I'd like to keep high airflow on the pcb and chips surfaces too because I believe it may play an important part in cooling.The pattern of holes attaching the heatsink to the bottom plate is different between batch #2 and batch #2. Batch #2 uses 7 holes, Batch #3 uses 5 holes.
Has anyone made a hole matching plate, perhaps 3 mm aluminum with countersunk holes?
lastbit in terms of what your doing you might want to try this as modding not uploaded all details yet but this s on a batch 2 unit and working out the layout for batch 3 will have details on my website when I get around to it.
Thanks crazyearner. Indeed something along the lines of what you did. But batch#3 id different, each 2 modules are arranged in mirror with heatsinks facing one another. And I'd like to keep high airflow on the pcb and chips surfaces too because I believe it may play an important part in cooling.
If migrate, only to Burnin board.
1 -20 chip instead 16.
2 - Very stable work at 400MHz
3 - programmable VR
1 -20 chip instead 16.
2 - Very stable work at 400MHz
3 - programmable VR
Well, you could always buy blank Klondike boards, then remove the chips and re-solder them 
. A 3-module Avalon would take 15 K16s. If you could run them at 400, you'd get a ~14% improvement over 350.
. A 3-module Avalon would take 15 K16s. If you could run them at 400, you'd get a ~14% improvement over 350. I measure my board with my 100MHz oscilloscope with 1.3V mod and did not see noise on power lines. I check it now after over 10 days mining.
About drop:
Standby: 1.298V
395MHz:
1.278 on coil VR and nearest capacitor
1.268 first two chip
1.228 last chip.
I solder silver-plated wire 0,8mm across one board and check how its help.
Thanks for the info. It looks like it's more work to do. Loosing 3% hashrate for voltage drops would be sad.
If all you have to do is lower some resistance to get it to 1.2v, or 1.3v - couldn't you actually just solder another resistor in parallel to lower the resistance the correct amount? You wouldn't need to remove anything that way.
One problem, of course is that the boards would run hotter even at the same clock speeds...
Its no problem set 1.3V or higher. VR can supply more amps.One problem, of course is that the boards would run hotter even at the same clock speeds...
The real problem now are cheap PCB
Too thin copper layer generate huge voltage drop on end of board. Thanks lastbit and GandalfG for the info. I have access to a nice 12ghz oscilloscope and will take noise and ripple measurements of the output of the VR and see if it gets unstable past 20a.
Just took some measurements. At the top of the board closest to the VR im seeing 1.2v at the bottom im seeing 1.15v! Im surprised to see so much of a drop! They must have cheeped out on the amount of copper on the board.
Just took some measurements. At the top of the board closest to the VR im seeing 1.2v at the bottom im seeing 1.15v! Im surprised to see so much of a drop! They must have cheeped out on the amount of copper on the board.
I measure my board with my 100MHz oscilloscope with 1.3V mod and did not see noise on power lines. I check it now after over 10 days mining.
About drop:
Standby: 1.298V
395MHz:
1.278 on coil VR and nearest capacitor
1.268 first two chip
1.228 last chip.
I solder silver-plated wire 0,8mm across one board and check how its help.
If all you have to do is lower some resistance to get it to 1.2v, or 1.3v - couldn't you actually just solder another resistor in parallel to lower the resistance the correct amount? You wouldn't need to remove anything that way.
One problem, of course is that the boards would run hotter even at the same clock speeds...
One problem, of course is that the boards would run hotter even at the same clock speeds...
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