GRIDSEED G-BLADE Overclocking 7Mh/s, improvements and repair

[J4bberwock]

I've also blown a mosfet on one of my blades, as usual, it's the upper gate one that is alone. I suspect that shrinking the design from 2 upper + 2 lower to 1 upper + 2 lower fet puts stress on the single when overclocked. I'll solder a replacement one tomorrow. IRFH7004 doesn't seem to work in this place or something else is shorted. I'll try irfb7437 that is proved working on a pod or I'll replace with the newer components used by gridseed as I have some.
experiments so far:

Upper gate, pin 19 -> 5302 or CSD16321 or irfb7437 (works on pod) irfh7004 doesn't work on blade?
Lower gate, pin 2 -> dual 5300 or dual CSD 17556


I've found alternate soldering points on the blade for the gate of lower fets that will make experiments easier with fets soldered outside of the blade

update on the blade, I can confirm that irfh7004 don't work on upper gate when you have dual 5300 on lower gate.
but CSD16321 works with dual 5300 on lower gate. I received a pod with this configuration, and I tried it on the blade.
It's happily hashing again.

next step will be external quad parallel fets on each gate to feed the up1509 before trying complete external powerboard thaqt could be piggybacked to a blade

we still need a good TO-220 candidate for lower gate

as a side note, if you do replace the power plug with screw terminal like me, put them on the back of the board, that will allow for more space to solder the upper gate mosfet when it will die.
I've melted half the screw terminal with my hot air station when desoldering and resoldering the fet.
It will also be easier to screw/unscrew.

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[Blisk]

great I will also check which can be good replace for lower gate.
Don't know what you mean with...

I've melted half the screw terminal with my hot air station when desoldering and resoldering the fet.
It will also be easier to screw/unscrew.

[J4bberwock]

great I will also check which can be good replace for lower gate.
Don't know what you mean with...

I've melted half the screw terminal with my hot air station when desoldering and resoldering the fet.
It will also be easier to screw/unscrew.

I will add pics.

As far as I now understand the mosfet used with the buck converter, you need lower Rdson for the lower gate ones, and higher Rdson for the higher gate one(s)

5300 is 1.3mohm (dual lower gate)
CSD17556 is 1.4mohm (lower gate)
5301 is 1.85mohm (some of you have seen it instead of the 5002 higher gate)
5302 is 2.1mohm (single higher gate)
CSD16321 is 2.4mohm (higherr gate)

7437 is 2.0mohm, that's why it works as replacement for 5302
7430 is 1.4mohm with TO-220 package. it should work as the lower gate with either 5302 or 7437 as the higher gate

7004 is 1.4mohm, should work as lower gate, that's why it wasn't working when I put it in place of 5302 (blown higher gate)

The last one I'm still waiting for delivery is
1404 with 4.0mohm rdson.
it should work ok as a higher gate.

So I have 2 options

1404 higher gate and 7437 lower gate (lowest rdson)

ordering 7430 to have 7437 higher gate and 7430 lower gate

[Blisk]

so I already got IRFB7437
and I am waiting to get 1404
and that should work?

let me know if you test it if it works.
I need first to find out why my blades stops to mine after that I will change mosfets.

[J4bberwock]

so I already got IRFB7437
and I am waiting to get 1404
and that should work?

let me know if you test it if it works.
I need first to find out why my blades stops to mine after that I will change mosfets.

irfb7437 and 1404 could work.
7437 and 7430 should work, I can't see any reasion they won't, but I'm not an electronics guru, just experimenting and learning very fast.

if your blades stop with cpuminer too, it should be hardware related.
try at least to cool the 3 mosfets over their junction temperature, they do stop to work and the blade stops hashing.
If you have the libusb error with cgminer, direct connecting to the computer with a short usb cable, could help too.

irfb7430 ordered, I should receive them next week.
In the meantime, I'll prepare a board to fast swap the to-220 mosfets and post a few pics of the easiest soldering points for upper and lower gates external fets
I'll also look for good solder points for a complete external powerboard.

[J4bberwock]

so I already got IRFB7437
and I am waiting to get 1404
and that should work?

let me know if you test it if it works.
I need first to find out why my blades stops to mine after that I will change mosfets.

regarding your trouble with blade stopping to send shares, I also have similar trouble when for some reasons the fan stops to work.
mosfets overheating, and closing.

[evocoins]

I haven't got any problems with my two Gridseed's I bought three weeks ago from monster-asic.com. Fans working fine, no problem here. But yes, 7 MH is a bit optimistic, I managed to get mine to 6.5 MH

[Blisk]

No fan works fully and I even tried with hand how hot board is but not that hot.
I assume maybe can be a power plug, one stops to work something is disconnected in it.
After a while and high current maybe connection broke, I will see tomorrow I will change it.
Because it is no reason why after more than one month working with no problems suddenly not working anymore

[J4bberwock]

No fan works fully and I even tried with hand how hot board is but not that hot.
I assume maybe can be a power plug, one stops to work something is disconnected in it.
After a while and high current maybe connection broke, I will see tomorrow I will change it.
Because it is no reason why after more than one month working with no problems suddenly not working anymore

Could be MOSFET or main capacitor wearing. The powerboard is already close to the limits, even non overclocked.

[Blisk]

I think I found out the problem.
I read on some froum that COM ports over 10 can be problem, so I put my Blades under 10 com ports and I will see.

[J4bberwock]

I think I found out the problem.
I read on some froum that COM ports over 10 can be problem, so I put my Blades under 10 com ports and I will see.

com70/71 here

[Blisk]

I think I found out the problem.
I read on some froum that COM ports over 10 can be problem, so I put my Blades under 10 com ports and I will see.

com70/71 here

I changed ports and will see if that works. Because really com prots are the only thing I changed on it.

[Blisk]

It's not that, blades stops to work again

[J4bberwock]

It's not that, blades stops to work again

what is the exact error?
cpuminer still working but no share sent at all?
at least, add the timeout command
--gc3355-timeout=120
it will restart the blades if no shares sent in 120 seconds so less money lost
here is my commandline
minerd-gc3355 --no-refresh --gc3355-timeout=120 --log --gc3355=\\.\COM71,\\.\COM70 -c config.json

the config.json file have the pools and frequency settings and it looks like it needs to be named like this.

[Blisk]

thanks didn't know about timeout.
Yes cgminer works but no shares
what do you have in config.json?

[J4bberwock]

thanks didn't know about timeout.
Yes cgminer works but no shares
what do you have in config.json?

here is the json file
first pool is main pool. everything after will be backup pools
{
    "gc3355" : [
        "\\\\.\\COM71",
        "\\\\.\\COM70"
    ],   
    "pools" : [
        {
            "url" : "stratum+tcp://eu2.multipool.us:7777",
            "user" : "     ",
            "pass" : "x"
        },
        {
            "url" : "stratum+tcp://eu.multipool.us:7777",
            "user" : "     ",
            "pass" : "x"
        }
    ],
    "freq" : "1063"

[styson]

Can you please give me the values for the 2 small capacitors by the power connector on the Blade, they are next to the 3 Ferrite beads ?

Thanks,

[J4bberwock]

Can you please give me the values for the 2 small capacitors by the power connector on the Blade, they are next to the 3 Ferrite beads ?

Thanks,

it you are looking for the 2 little ones between the 3 ferrites and the 2 bigger capacitors, they should be c9 and c10 from 8 chips schematics
10uF 6.3v 0603 size

[styson]

Lost them while busy trying to find a short on the board, 3 Ferrites were blown and the FET is shorted !!! Waiting for replacement FET's now.

Thanks J4bberwock

[Blisk]

J4bberwock
Thanks I asked for setting for com ports
I changed today power plugs and for now looks like it works ok.