Topic: GRIDSEED G-BLADE Overclocking 7Mh/s, improvements and repair - page 20. (Read 74155 times)

ive done direct wiring on motherboards to fix vdroop and stabilise memory. So in theory, your idea could work.

Anyone up to test it ?

Remember to remove the 2 ferrite beads, and replace them with thick solder. Otherwise you will damage your blade.

I can't see any reason for choosing 2 different ones, but one is for a channel, the second one is for a different channel.
Original design used 2 per channel and the same ones
UG and LG going to pin 2 and pin 19 of up1509

All fets were named 09N03 in the schematics.

here is the datasheet for it
http://www.infineon.com/dgdl/IPD09N03LA_Rev2.1_G.pdf?folderId=db3a304412b407950112b408e8c90004&fileId=db3a304412b407950112b429dca44214

On the 5 chips pod, the design shows only 1 for UG (pin2).

So we have
Upper gate, pin 19 -> 5302 or CSD16321
Lower gate, pin 2 -> dual 5300 or dual CSD 17556

We should be able to use the same fets everywhere.

So, I pulled off the bridge mod w/ a tube of electric paint from RS for 8$ ....
Did it on 2x Gblades
Results are 875mhz ... 3 HW in 40mins @ vardiff 256  ... total between the 2 gblades

I would think thats a decent HW rate, less than .2% or so...

The next thing I would like to figure out is a way to overcome the insane voltage drop measured from the first yellow SM cap( in the VRM area) to the second SM cap(in the ASIC area).
On both my gblades there is a drop of .05v between these 2 sections alone.
The drop from the 2nd SM cap to the 4th SM cap(last one in ASIC area) is not nearly as high a drop.

Im wondering, for any of u electronics gurus out there, would soldering a 20 AWG wire from the - / + of the first yellow SM cap in VRM area to the respective legs on the 3rd SM camp(in middle of ASIC area), provide a more stable current flow between the sections of the blade? ... hence resulting in less voltage loss?

Ive seen a mod similar to this performed on avalon gen1 modules. It helped significantly.

Also, Im gonna guestimate that this is why we cant get the same clocks @ same voltages compared to the pods(@ same HW rate).
I highly doubt the pods would have this crazy voltage drop due to their size and layout and small # of chips.

If anyone could chime in on this that would be wonderful! Im dying to try it but I dont wanna destroy my blade....

this.
should be cleared before we happily throw random chips in

Ok, thanks, when you make it please let me know and I will also try what I intent to do and let you know how it works.

I'd simply use the reset switch for the USB
It should be enough

A switch to disconnect your resistor from the board should also work.

Up to 50K, you should be fine if you use screw terminals (easier than direct wiring), I've already tested it.
47K with the standard connector, and the connector that plugs to the board have melted in a matter of minutes.
Up to 50k, the worst thing I've seen is the board stopping hashing after 1 or 2 minutes because the VRM went into heat protection and cut the line until they cool down.

ok let me know please in fev days I also will get those and will modify my blades.
So what you change is those mosfets, resistor and ferrite?
And direct wires to powering blades?
Is there anything else?
instead of resistor I will put on this potentiometer
http://www.rapidonline.com/electronic-components/20r-wr3006p-3-4-multi-turn-cermet-pot-68-0266

it is precise one I will use about 68Kohm

can you advise me which part to switch off and blade won't mine anymore and it is low power so I can use dip switch to stop mining?

IRFB7437 works, 1404 is ordered, but if you can have both at the same price, take the one that works for now.

I'll test the blade with IRFB7437 and 47K resistor in a day or 2

I thought to use heatsink like this
http://www.susan-parker.co.uk/zeus-heatsink-sk158-1a.jpg

about legs I will bend it to work it out or even solder some hard wire to it to be long enough.

so which mosfet you reccomend?
IRFB7437 or IRF1404 for Q6, Q7, Q8?
I ask you because I didn't research about it as much as you do.
Price is almost the same even if you look at ebay

The orientation of the pqfn isn't the same on the 3 ones, so you won't be able to do it like this.
plus the legs of the TO-220 will be too short to bend them back to the other side

Since there will be 3 TO-220 next to each other, I'll probably go for a heatsink for the 3 of them and I'll let it stay on the PCB without soldering it, maybe glued with non conductive glue.
Look inside of a computer PSU to have an idea of what I mean, except in the PSU, the heatsink is soldered to the ground of PCB.

I have a few dead old PSU that I can take the heatsinks off for this project

Could be onto something

this  IRFB7437 can replace all 3 chips?  IRFH5300/5301/5302

Why than they use two  IRF5300
and one IRFH5301?

what is difference with IRF1404 and IRFB7437? less power?

I found IRFB7437 for 1,17€ pcs

here is pic what I think will do with to-220 mosfet
this is look from a side

TO-220 replacement should be done safely with IRFB7437 in place of IRFH5300/5301/5302
I'll also try IRF1404 that I can get way cheaper and is easier to source.

If I understant you correctly, you will glue the heatsink on board "A" next to the USB chip, over the empty header holes, to screw on it the TO-220 connected to board "B"
Am I right?
It could work, but you will need precise work because the solder pad for the Gate of the TO-220 is small and the soldering can easily break if stressed.

I have in my old not working computer psu some ferrits like this I think I will use these which are more pwerfull just need to measure it.
they looks something like this
http://info.ee.surrey.ac.uk/Workshop/advice/coils/BHCkt/frte01pic.jpg

Also I see you have all figured out which mosfets are replacable can you write which to-220 will you use for those 3 - 2x IRF5300 and 1x IRFH5301?

I have also figure out how to do it with TO-220
I will glue a big heatsink on the other side of board where are no chips and at the edges I will mount on it all TO-220.
Of corse with an insulation between them.
So they will be mounted on large heatsink and fan which is already on blades will coll it too.
What do you think about this?

He has blown ferrite beads, so he sent the pod to me to try to revive it.

one power mosfet was shorted, so I replaced it with IRFB7437.

You can see on the picture that when exploding, the ferrite beads have badly damaged the PCB near the solder points for the fan.

If you do TO-220 conversion, beware the Gate/Source/Drain could be misplaced.

So here comes Frankenpod







It works just fine, I disconnected it after a few seconds to avoid overheating the GC3355, but even the 7437 was hot. It will need active cooling with dissipator.

I thought the same other day, to use to-220 you can cool it better and still can be almost at the same spot so you don't have dissapation on wires there is high current here.

Why they chaneg chips which are almost the same, only the price can be factor. They get chips for much lower price.
Did you find replacement for IRFH5301 also, to-220 housing?

I think I will order chips tomorrow because it takes almost 3 weeks to get it.

CryptKeeper's pod with IRFB7437?
he also did some modifications?
where is his topic?

it is pin to pin compatible, higher amps, higher amps at high temperature, so we should get better overclocking with it.
But we'd better go for to-220 packages since we have much more room available on the blades.
I'm trying to revive CryptKeeper's pod with IRFB7437.
If it goes back to life, I'll try replacing all the mosfets with TO-220 on one PCB of my blades.

BTW, why did they decide to go for 2 different types?

IRF00/5301/5302 or CSD17556/16321 do have almost the same datacheets.
I'm not an expert, but they are all N-channel power mosfets with almost the same values.

STL160N3LLH6
so this can replace IRF5300?

Hi Wolfey,

I'm still waiting for my no clean SMD flux paste to arrive.
I received some heatsinks for the back of the PCB, I should receive my spacers for wide body at the beginning of next week.

I do expect that we are reaching the limits on the 2x IRF5300 and 1x IRFH5301 or 2x CSD17556 and 1x CSD16321 because they can stand a much lower constant load while they are hot than when they are cold.
So overcurrent built in protection closes the gate.

IRF7004 is a little better, but not that much.
Best bet would be something like this one as direct replacement
http://www.st.com/web/en/resource/technical/document/datasheet/CD00291104.pdf
The worst case will be that the up1509 reaches its limits, but as it's far from hot, it should still be ok for some extra amps.

Anyway, piggyback powerboard could be done, I'm still working on something.

Hello J4! What's the latest progress? News?
You haven't seen any magic black smoke of late, have you? 
Hope not!

Fill us in. You've been missing for a few days since you threatened to achieve 8MHs or magic black smoke   

FYI....
I've had my 26 overclocked pods hashing away at as high at 17980KHs pool side. Lots of time hovering at 12MHs to 14MHs with very little to no HW errors.

Hope all is well, mate!

Wolfey2014