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

I have the something happen to me, the tip of the power supply touched the heatsink. What I dont know is what component got fired, when I plug in the power the fans turns but no led action and the computer doesn't pickup the device when plugged in. Any help would be appreciated also no signs of burn marks and haven't modded the device. Thank you.

The PCB program shows:

Component Class:      IC
Device Type:          FERRITE BEAD_FB0805_300OHM@100M
Value:              300ohm@100MHz,1.5A

what would I be looking for when testing it? 

If you have a DVM handy, unsolder the FB, then test to see if either or both terminals are shorted to ground - DC. If so, FRIED!
If not, maybe it will come back to life. I doubt it though. From the sound of your description, you cooked it!
Try at your own risk etc.
Good luck!
Wolfey2014

Happydaze or someone,
Can you tell me the value of this component.  Also is it a resistor or a ferrite board?  Mine is blown due to adapter tip touching the heatsink.  Is the gridseed trashed or can i replace this component with something else and hope nothing else got fried other than it and my powered USB hub.  I have not modded anything on this yet.

https://i.imgur.com/6QfZ95q.jpg

And, way less profitable too! ;p

My un-moded units have been extremely stable

You are lucky, that is true.
Latest failure, looks like both FBs got blown off cleanly 

Sounds like a few of a bad batch of miners that got through QC - of which is known to be fairly poor to piss poor anyway - are rearing their ugly little heads.
I've had 25 personally modified pods running for months and months with no issues!
Also, things tend to just work right when I'm around anyway

Happy Holidays Folks!
Wolfey2014

Pea Essssssssssssss, they've all paid for themselves a few times over by now too! One of the lucky ones I am

I've now had 5 out of 10 Gridseeds blow FB23&FB24 in the past 6 months. Replacing the beads just makes them blow again. Obviously the R52 volt mod was not a good idea, I'm guessing it's only a matter of time till the rest of them die.

Update for my repair

Replacing the mosfet did not fix the issue.  With mosfet replaced I still had the same nonworking fan issue. I removed fb26 and have yet to get a replacement.  I did supply 12v through the jack in order to test with FB26 removed.  Wasn't for sure if that would cause an issue, but anyway the same mosfet blew again after about 40 seconds of 12v applied via the 12v jack.

I also visibly noticed some type of crystalline material oozing out of the p1707q IC located not far from FB 23/24, so I am assuming that is blown also.  The replacement for p1707q is here (http://www.adafruit.com/datasheets/MP2307_r1.9.pdf).  Have yet to order it.  Plus my FB26 wont ship till November.  Still might use a FB23 in place of FB26 temporarily.

http://i61.tinypic.com/29ctp3r.jpg

Any comments, suggestions or criticism welcome :-)

Never said I did the VoltMod

...but yea, for those that do: Do NOT try to mine BTC

The Gridseed can NOT run in BTC mode with VoltMod...even modest Vmod will rise the power consumption above the MOSFETs ability to handle...Capisco...

Just don't try BTC mode , when overvolt...You will blow MOSFETs ...or something else...at your risk...

BTC mode is fine only at stock voltage...

ZiG

Heya wors

Glad ya got it sorted :-)

Finally got my mosfet replaced today.  I still need to replace FB26.. I cannot find the part in stock anywhere.  I wonder, can I use one of the FB 23/24 and temporarily replace the FB 26 with the 23/24 while I wait for the backorded part?  I realize doing this would be replacing the original part with one with double the current capacity.

Anyone have any comments or suggestions about doing this?

I had similar problems before I modded them with 47.7k if I was mining in dual mode. They are just to unstable and if i have to watch it it will profit less. Maybe I will do the bridge mode with switch to use scrypt only (I want switch!) but I still don't know for sure if those bridges revert all to stock (ok 36k is little bigger than 33k) and it support dual mode for sure?

EDIT: Just bought AntMiner for SHA256 so I will leave GridSeeds on scrypt
foz, how is your repair?

I tried dual mining but found that while doing so gridseeds would start falling off slowly (zombie) requiring them to be power cycled. Since I have them running at a remote location and can not easily power cycle I changed back to just mining scrypt as that is solid.

Thank you guys for help! This thread is so cool

Guess what. My GridSeed works after replacing FETs that come to EU for free faster than light!

Still now sure what caused FB23&24 to melt. After replacing them FET on another GridSeed burned a bit. I was thinking what happened, Wolfey said I should check connectors, good point cos they are home made and everyone is different But nah then I was thinking further, I wrote in later posts that I mine on my developing machine, that is ultra smart. After I replaced FBs GridSeed started to work again, and FET now caused new short on 12V and the closest GridSeed started to suffer. I am just happy that I shut down machine right time. Guys you should tell me that if one GridSeed pops short happens and this is bad. I have to immediately replace FET that is burned a bit, Gridseed is mining fine but it will blow some day! I should really run them on separate power supplies.

Now that I replaced FET I have mini problem. I downclocked to 1163MHz before starting and something wasn't ok. The reported speed was way over 500khash. I downclocked even more to 1100MHz but 470khash is to much. Is the new FET responsible for 10% gain? The only other thing could be three years old mining PSU that works on 11.5V   (i am on another testing machine now) ...
http://i60.tinypic.com/2mpwl08.png

Now that this works (I really hoped it won't so I could use heatsink for another home project ) I would like to revert my R52 mod. If I read thread right I just place two switches instead of bridges to revert to 36k resistor. Just one thing I would like to know can I dual mode if I do this? Dual Mining is more profitable ad I have free electricity so I would like to dual mine no just SHA256 or just Scrypt but dual mode.

 

What were you using to power them up? Perhaps the power supply caused the first FET to blow? If the power is dirty or unregulated or too high, this could happen.
The reason I ask is because when you run them on a separate power supply they don't FRY!
Check the power cords and connectors too.
If you have a DVM, check the voltage at all connectors.
The answer to your problem is in there somewhere. Just remember to keep it simple! The ol' KISS rule will set you free if you apply it and burn your ars if you don't
Good luck!
Wolfey2014

Hi wors

I am new to this also but that looks like the right part for FB 23/24.

I'll let some of the other more experienced members comment on your other questions. 

Hoping my mosfet will be here by the end of the week....hoping I can get the old one off without too much trouble also 

Ok I got part from Farnell (FB 23&24). I am not sure it is the right one (FERRITE BEAD, 0.06OHM, 3A 1206) (742792121).
I resoldered red wire and two ferrite beads. Plugged the thing into the PC, fan spinned ok.

Then I replugged everything and started the PC... Waited 5 second, and the smoke come from another gridseed
Opened it and there was a hole in the MOSFET (I can see PCB under small 1x1mm hole), even that chip near R52 seems to be weird?

I retested every single one on standalone power supply and all works, even the one that smoke comes from. I plugged all back to PC and right now they are mining with no problem?!? Now for 1hour.

Lets go to real problem. Why my newly repaired GridSeed caused another one to blow FET? I am afraid to ever put that thing back into the PC. Right now it doesn't spin the fan anymore on standalone power supply.

EDIT: I just ordered three free samples (FETs) from TI (CSD17552Q5A ) and will replace FET on failing one. FBs were not enough.