Topic: GridSeed 5-chip USB miner voltage mod - page 17. (Read 156980 times)

Thanks for quick replay, any idea why would it might blow? Also is it 0603 ?

Ferrite Beads. 
300ohm@100MHz,3A

Does anybody know what this two parts(yellow marked)? my 5volt mode with 49.9k resistor swapped pot is blown(13 out of 20 GS) after 3 days 24/7 run for unknown reason. windows still recognize the com port and 5 chip still visible in cpuminer. if anybody knows the value of this two i might try to change this to see if it works.

I think they are marked as F824 & F823

UDATE ON POWERING THE GRIDS WITH 5v
I found it ran nicely at stock settings - 650 mhz .
Pulled 0.77A and had a DVD volatge of 1.46. hash rate of about 250. For some reson reason the though i was only able to get one type of grid running with 5v. The newer type wiht the SMD leds.
Once modded though the hasrate dropped through the floor BIG TIME! went down to about 20-70! ouch! so back to 12 v it was.
So basically anyone runnign these at stock no overcloking or modding - why woud you though! - can run these on 5v wihtout effecting the hasrate and save on enery costs.

summary stock (no modsS!!! ) 650 - never tested 850 sorry - runs fine (SMD LED version only).
DO NOT run a modded grid on 5V your hashrate suffers.Even at 650!

this has been discussed and mentioned about the risks of shortening out componets etc.
there been many discussion about pads or paste or stock! we all know where you stand wolfey
thermal paste is better - but more messy!
the bits that are touching seem to be the crystal - ive dented mine! - and the chip next to it. theres the option to get the rimmel out and take a bit out of the center column on the heatsink.
I say use the thermal paste underside, thats where most heat goes! trim the heatsink, on top, pads - i use a bit of thermal paste as well to help with adhesion to the chips. be warned though

https://bitcointalksearch.org/topic/m.6361304 - concerning the underside of the PCB!

to save some pad yher is no reson to cover the whole of the center column in thermal pad. just cover the tops of the chips - 4 small squares! you can make the one near the power supply a bit bigger to cover the crystal and chip.
and i found Zig post as well

EDIT : yeah adding the link to Zig post WOULD help : https://bitcointalksearch.org/topic/m.6365619

hope this helps. theres no clean answer on this topic - just lots of advie and recommendaitons - good and bad , its really a person preference, until we get test data on temp and paste vs pads vs stock, but i dont see that happening anytime soon One last thing dont tighen the screw too much risk of short and risk of damage to PCB - i over tighten and dented my crystal!

Ofc. Im not going to bother with attempting to RMA it.
Anyway. I undid the voltmod and still no improvement. Double checked all PCB components and found nothing wrong again. Going to wash it with toothbrush and cleaner. If theres some physical disruption then washing cleans it up. If theres faulty component, then i will probably never find it. So washing is my last hope.  

If you remove the thermal pad on the back of the unit, you have to insulate the exposed contacts otherwise a short WILL occur.  If you chose to use paste on the top of the chips instead of the thermal pad, then chances are you'll need to mill out part of the heatsink so that it makes full contact to all five gc3355 chips.  There are 2 components (a 6-pin chip and the crystal) which are taller than the gc3355 chips.  If you crank down the heatsink, you'll put a lot of pressure on those two components and likely break them or at least break the solder connection to the board.  Thermal pads may not have level of heat transfer that the thermal paste does, but they're a much easier option.

To everyone that has done this mod, have any of you needed to upgrade cooling on the unit?

I was using thermal compound on mine, and one of mine shorted out and fried the gridseed. Apparently when you remove the pad, the screws compress down and potentially touch the unit.

Are you guys just leaving stock pads on there? I would like to get aftermarket pads, but to upgrade cooling on 50 of my seeds will be like $200 in thermal pads lol.

The thermal interface grease makes me paranoid now because of the 1 unit that fried.

modding voids warranty!

got my 33mhz too! first got to get them hash stable before i can even consider trying it on any

try wolfey version of the mod! same thing but uses a 1/8 axle resistor - so bit easy to handle, alos solder it different points, but whihc are electrical the same. He done several post on his mod, sure if you ask he hee point the page - maybe hell give you a link to it too. its sound as is zig mod electircal they are both sound mods. wolfey mod is in here some where many pages ago!

Sounds like a RMA...back to GAW...72 Gridseeds kit...right...?

I got the same kit delivered yesterday...best bang for the money...

yeah, basic 2+2 dots solder together voltmod. Only one miner out of 72 is having this problem.

Did you do a volt mod ...and which one...?

I have wierd anomaly with one gridseed 5chipper. It seems that only one out of 5chips is working. It hashes 80khs, but gives no HW errors.
I checked its PCB and saw no problems.
Any ideas?

Go here https://bitcointalksearch.org/topic/guide-jesses-official-overclocking-voltmod-guide-for-g-blade-gridseeds-v2-575315 for good pictures and a nice writeup of the steps you need to take.  Good luck.

There are no reason to upgrade your crystal. Downgrading is much better, because it decreases the frequency steps.

27MHz arrived at home, so I'll test it on one pod if it still hashes, I'll go for 33Mhz or close
I'm wondering where we can see the difference since the pod only uses the oscillator/crystal as a clock reference.
1000Mhz setting will actually be 1080, but where/how to check?

I am not a professional solderer but I am good at things

I bought the whole kit for under $100 with hot air station and all, and guess what? I now dont even use this ALl I use is

A pair of tweezers , a Pencil Iron, Peice of Solder, Flux , Toothbrush, Metholayed spirits to clean ANDDD a Magnifying stand ALL PURCHASED for under $50

Tiny 0402 SMD 49.9k No problems  --- I am in Australia Sydney if anyone wants

It now takes me just under 10min to fully Thermal Cool, Solder, Test and re- assemle a Pod, This is with the 49.9k SMD 0402

I have now done almost 30 Pods still quite abit to go , But I am getting there

Go back to page 1, search for - wolfey2014 - all my posts will come up, and all shall be revealed to you