Sandor just making sure that I am supposed to place a shunt across the two yellow lines to gain the boost. Thanks

You mean do not ask him on this forum. Because I have been communicating with Jack through my on private email and a few times on this forums PMing system. By coincidence I am expecting my second delivery from DHL today. I do not intentionally over step by bounds on this forum because some members, to put it nicely get very touchy on some matters, so being fairly new to this forum I did not know what part you play. But I thank you for your response.

Ok, almost there, but still getting an error as follows:

[2014-03-18 19:59:51] Starting Stratum on stratum+tcp://usa.wemineltc.com:3336
[2014-03-18 19:59:51] 0: GC3355 chip mining thread started, in SINGLE mode
[2014-03-18 19:59:51] 0: Open UART device COM6
[2014-03-18 19:59:51] 0: Set GC3355 core frequency to 600Mhz
[2014-03-18 20:00:12] stratum_recv_line failed
[2014-03-18 20:00:12] ...retry after 30 seconds
[2014-03-18 20:01:03] stratum_recv_line failed
[2014-03-18 20:01:03] ...retry after 30 seconds

Excellent! I knew there had to be a further hardware mod 'jumper' to get stable operation at 1.25V without converting over to a different mining program. I'm using cpuminer and am quite satisfied with it since I have a very small farm anyway.
One thing that still bugs me though is having to reset the USB ports every 24+/- hours.
Anyway, I can make the jumper mods easily as I own a professional Weller soldering station with adjustable temp, very fine tip assortment, de-soldering etc. So no problems making the mods.

I wonder though, have either of you chaps tried seeing if any of the existing header's pins correspond to either of those two jumper points? Or is that header simply a serial port connection. I haven't studied the schematic yet so I realize this may be a stupid question.  

Anyway, I'm very interested in this mod for my own miners. Having done years of laboratory level R&D in electronics, this stuff is a piece of cake!

Have the two jumpers stabilized the GS units well enough to overclock above 950 yet?
Man, if we can get these little buggers running at 500KH/s, that would be fantastic!
But, 400KH/s ain't nothin to laugh at either

I have all my units fanless now. If necessary, I can simply use 1 or 2 fans to blow air on the fins indirectly which will of course keep them running cooler.

I might be interested in making this mod for others too if the money is right.
They'd be responsible for all shipping costs and insurance etc. etc.
I'll figure out what is a fair price to charge per mod later if anyone shows interest.

Thanks for coming up with this mod. Sure saved me some time and hassle.
Wolfey2014

Hey sandor, i am wondering whats the diff doing the hardware mod vs the software mod you are coming out with?

both are able to be overclocked to 950 stable. Does the software update somehow increase voltage? Just curious to see if i should perform the hardware mod

Link to the Voldmod thread.

https://bitcointalk.org/index.php?topic=519112  

It doesn't. Cooling is not the the problem in scrypt only mode. You can remove the fan completely and in scrypt mode the heat sink will barely warm up. In fact, you can run scrypt without a heat sink at all. The power draw is so low in scrypt mode (approximately 7 watts without the fan) the chips don't even get toasty. Use the heatsink and fan to keep your beer cool.

The heat sink and fan are for bitcoin only/dual mode. That will heat things up (I haven't tested it myself, but others have reported a 60 watt draw).

Considering the number of people who have tried pushing these things to their limits, I seriously doubt claims that these things can be run at anything above 900 with any sort of efficiency. The people on this board aren't stupid. I'm waiting to see what this guy posts. I'm betting he'll have a hashrate of 450 kh/s but almost no submitted shares due to rejections and errors.

This allows you to have a stable overclock without the special version of CGminer and voltage=1???

Have you released the new firmware for your LA controllers yet?

If I perform the mod, then I want to go back to mining at 600-850mhz again for some reason, that still works? (but still using 2W more?)

If anyone interested I've modified Andareed's version of cgminer a bit to let you better finetune the gridseed units. There's a big variance in the resistors they used as voltage references so every unit has a different maximum frequency they can run at.

https://github.com/girnyau/cgminer-gc3355

New frequency table: 800, 813, 825, 838, 850, 863, 875, 888, 900, 913, 925, 938, 950, 963, 975, 988, 1000, 1013, 1025, 1038, 1050, 1063, 1075, 1088, 1100, 1113, 1125, 1138, 1150, 1163, 1175, 1188, 1200

You won't need the ghz ones however unless highly overvolted

You can also define a base frequency as usual, then set per device frequencies by the units' serial number if you want:

--gridseed-options freq=888 --gridseed-freq 8D74488A4949=900,8D96227B5449=900,8D7357785355=875

Factory units running since ~48 hours without any hw mods but the fans desoldered:

 cgminer version 3.7.2 - Started: [2014-03-16 13:23:19]
--------------------------------------------------------------------------------
 (5s):1.891M (avg):1.888Mh/s | A:3357360  R:4832  HW:228  WU:10.5/m
 ST: 2  SS: 0  NB: 950  LW: 34253  GF: 2  RF: 0
 Connected to litecoinpool.org diff 256 with stratum as user composeit.gridseed
 Block: 3a0bf6f9...  Diff:5.16K  Started: [22:08:37]  Best share: 18.8M
--------------------------------------------------------------------------------
 *P*ool management *S*ettings *D*isplay options *Q*uit
 GSD 0: 8D74488A4949  900 MHz | 382.0K/381.9Kh/s | A:653120 R:2176 HW:204
 GSD 1: 8D7135A35355  888 MHz | 376.9K/376.8Kh/s | A:670592 R:1152 HW:  6
 GSD 2: 8D96227B5449  900 MHz | 382.0K/381.9Kh/s | A:675936 R: 800 HW:  5
 GSD 3: 6D9323805251  888 MHz | 376.9K/376.8Kh/s | A:677392 R: 352 HW:  3
 GSD 4: 8D7357785355  875 MHz | 371.4K/371.3Kh/s | A:680320 R: 352 HW: 10
--------------------------------------------------------------------------------

Cheers

Andareed: did you measure the voltage output of the regulator to find out how much did this increase the voltage to? Just curious as to how much this mod changes the voltage.

neewbie here - been on this darn gridseed all weekend scouring the forums. but got it running. did a small mod. Flipped the fan - extended the cables and attached a shelf around the fan. It now removes the heat instead of blowing air onit to cool it down. also by lefting the fan 5 cm you improve the effiency of the fan by removing the dead center spot - which is exactly where the chips are located. anyway its running on scrypt only on bfgminer with clock - in the .bat file at least - of 1050! Early days only been running 25 mins but its at 446.8 avg 5s hash rate! and no hardware errors. gonna let it run over night see how stable it is. and ill post back plus upload some shots of the fan mod. tried to get it higher at 1150 bfgminer started but not the gridseed at 1250 bfgminer didnt start. thers maybe room for a bit more overclocking yet but not much its gonna be a resistor swap job. just got to track down the right one.

p.s got tonight screen shot just got to upload it and lost photobucket account details. tomorrow itll be - about 14:00 gmt

I've got a question regarding hardware errors on a Gridseed device....

I've got 1 miner in particular which seems to throw out way more HW errors than the other 9.  Typically the others may throw out 1 HW error from time to time...but this one averages 1 HW error each 1.5hrs or so.

I've tried the following:

1. Swap USB cable
2. Swap power cable
3. Swap USB port
4. Swaped which PSU its connected to

Regardless of what I do it seems this one miner is destined (or perhaps just a bit defective) and will continue to toss out HW errors.

I'm using freq=800 as it seems to be a balance between keeping 1 one from throwing errors and the other ones from "under" performing because I can't tune each miner individually.

My question is not what could be wrong, because I think this is just a crappy unit...but is it bad to keep using this miner and having it throw out HW errors?  I presume it just means this one miner will likely die well before the others?

Not really. Its gridseed, and the 5 chip ones only use 6,7 watts hashing 300 kh/s. 19200 khs divided by 300 is 64, so it would work.
Quote from the page I got it from: "19.2 MH/s worth of Scrypt mining hashrate is achievable by using a total of 64×5 Gridchip GC3355 processors or a total of 320 chips providing 300 KHS each." Lets not say it's a scam just yet, as 64 times 250 is $16000, or equivalent to buying 64 of them. They are saving money from not buying heatsinks, assembly, etc is my best guess.

Uhm.  Like I said, schedule a reboot every time one hangs or hourly just like the new controller box...

Can you confirm that this will be better than the recent 2.0.7 version of wiibox? I have been getting better stability with the wiibox controllers than LightningASIC V1 controllers.

Also, none of my USB hubs work without external power. Will this somehow fix this?