Quote from: soy on September 20, 2014, 02:48:16 PM

Quote from: soy on September 20, 2014, 02:04:04 PM

Quote from: montyfd on September 20, 2014, 08:24:45 AM

Quote from: soy on September 20, 2014, 05:47:25 AM

Quote from: soy on September 20, 2014, 01:55:07 AM

Quote from: soy on September 19, 2014, 09:02:31 PM

So the problem S3 was down around 430GH/s this morning and I decided to go over its probably reworked board, the board that had grossly over-tightened screws, but would try frequency change first.

It had been down to 430 so I tried changing the frequency to check out its effect on hashrate. In /etc/config/asic-freq I changed to f=225, rebooted and restarted cgminer to get a fresh time duration. I gave it some time but it came up very slowly only to 420 or so. And it was a cool morning! All the other machines were hashing perfectly. So, I tried again, this time with f=212.5 but again it came up slow and only to 417GH/s. So, I ripped it apart again.

I was going to concentrate on its ASICs at the hot end of the reworked board, but ended up getting distracted. What distracted me was that the board had marking in black ink at the far right under the top ASIC (on this board that would be near the intake fan). Might have been Chinese or a code of some kind. So, I cleaned that ACIC and the one under it with a spray of automobile brake cleaner such that all thermal paste was removed. Must be careful with the stuff as it will mar many plastics. I sprayed those ASICs cleaning around the pins, reapplied thermal compound to both sides of the blade and reassembled. The brake cleaner removed the notation marks on that blade. When I reassembled, for a change, I put the bad board on the right side facing the RJ45 connector.

I started it up then ran to the store and back. Right now the 'difficult' S3, at a frequency of 218.75, after 1hr 20min, has an average hashrate of 443.74GH/s. The temps are both 40° with fan speeds of 2040/1800. Time will tell.

Bummer. Up now over 6hrs and the hashrate has started to drop off. Could be to an increase in humidity and that the first S3 hasn't seen a similar tailing off of hashrate because its average is over a 12hr period but probably not as it's at 442.24GH/s utility 17 while the problem S3 has tailed off to 437.63, utility 15. Experience tells me it will continue to fall and tomorrow morning may be down around 420GH/s. Temps are 40/39 and fans 1920/1620. The good S3 has 40/38 3180/1920 and the good and questionable S3's are side by side. What jumps out are the higher fan speeds of the good S3.

Too bad. 1:30AM, checking the problem S3 and its hashrate has dropped to 429.01GH/s after 9hr 55min. Since I have two S3's, I could take what I think is the bad board and swap it into the other S3 and see if the good S3 then has a falling hashrate - just to make sure which board is bad. What's wrong with that is that the other S3, purchased from a reseller in the mid-west, runs fine (presently 441.67GH/s) while the problem S3 is from Florida (and that guy wants me to remove the 1 star Amazon rating, screw him, opened the bottom of a box from a good one and put the probably returned problem in and sent it out as new). By morning the problem S3 will likely be down to 420GH/s. Wonder if it's accumulating errors in an ASIC that then shuts down engines over time. Wonder if China sends more problem S3's to Florida than elsewhere given that Florida is a problem state like Shanghai crime before 1949. I'm not a happy camper.

soy

You are where many others have been 2 months ago. There are simply units like that and you probably wont be able to change it. And with 429 you cant complain, they were advertised with 441 +/- 5% if i remember correct.

As soon as I removed a heatsink I felt I was burning bridges regarding any return. Hadn't noticed at that point that the box had been opened at the bottom, clear tape slit all around, then resealed probably with a single strip of clear tape along the center bottom leaving the slit sides showing it had been opened. Then, because I said I wanted USPS, priority mail tape went around the box at its center over the replaced tape on the bottom and some haphazard slaps of priority tape on its side. I opened at the top. Kind of indicates he had this dog sitting there and a new unopened boxed S3 and kept the good one shipping the dog.

Right now the hashrate after 18hrs 17 minutes is 419.77GH/s, temps 38/39 while the good S3 from the mid-west sitting next to it has 441.88GH/s, temps 39/37. 441*.095=418.95

soy

And the price with shipping was $511.48. And Amazon probably sees a record of a return to this seller. Amazon returns are honored, albeit less so if opened and the heatsinks removed.

Swapping the questionable board from Florida into the good unit from the mid-west I notice that the good unit has two QC Passed stickers of different sizes/colors while the slow unit has a single QC Passed sticker large gold.

Perhaps a previous owner who returned the unit removed one QC sticker.

The questionable board is into the good S3 and both are now up and running. I'll wait a bit until both have gained some temperature then restart cgminer on both so as to have uptime duration coincide.

soy