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I am starting to wonder if it would just be easier to take the damn gc3355's off the boards, create a new pcb that can handle the power needed for SHA and start a password cracking service   |
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Damn I ordered the LQPF 48 (only on the 5 chip schematic) STM32 instead of the LQPF 64 for the blade, at least I also ordered samples from ST Micro of the 64 last week Hopefully it arrives asap Don't you just love free samples ? |
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Ok so finally got the STM32 off, what a bugger to get those LQFP IC's off, eventually had to use a bigger nozzle on the hot air and heat from directly above and apply slight sideways pressure with the tweezers, came right off, now just need to clean the excess solder and wait for the new part to arrive. Styson , are there some news about your fight against the stm32 ? And where did you get the firmware? Still waiting for the replacement STM32's, RS takes between 4-6 days to ship non stock items to South Africa. I got the firmware from Gades, just hope it is for the 40 Chip Gridseed |
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Ok so finally got the STM32 off, what a bugger to get those LQFP IC's off, eventually had to use a bigger nozzle on the hot air and heat from directly above and apply slight sideways pressure with the tweezers, came right off, now just need to clean the excess solder and wait for the new part to arrive.
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Yes the 2 parts to the right of the upper mosfet are capacitors, that's why it is easier to apply the heat from the left side pins, and lift carefully with tweezers from the left side, the solder on the pad should flow quickly and you can take the part off without blowing the capicitors off. The air should not be applied for long, I could not find anything in the datasheet though about the temperature and time you can apply the heat for. for the AME8805 it can be 300 degrees celsius for 10 seconds. Thanks for your suggestions, will keep them in mind. Looks like the STM32 is shorted, so have to wait for a replacement, and then hopefully I can get the firmware on there |
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Ok so I removed the ame8805 by the USB and there is still a short between 3.3v and ground, any idea's ? Will be check the STM32 for shorts tonight |
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One more question i forgot:
Is the burned upper Mosfet the reason why i have a short circuit when i plug the PCB to 12 V? There are sometihing like 50 Ohm between the measure points , so its completly far away from infinite and definitly damaged, but is this the reason why the power source goes instantly down? Or maybe there are more burned parts ?
Yes it's definitely the reason for the power supply going off I had the same happen to my blade, replace the upper mosfet with CSD16321Q5 Also be carefully to not pull the mosfet off, let the hot air station reach temperature for a while, then apply heat to the left of it, it should be able to slide right off, do not pull it, if the solder is not molten it will pull the tracks from the board and cause damage. ;-) |
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Hey Freeman,
The Larger size FB's are Ferrite Beads, 300 ohm 100Mhz 3A 1206, the smaller ones are 300 ohm 100Mhz 1.5A 0805
A lot of the guys just bypass the ferrites with a 0 ohm resistor or bridge with solder, that's if you have a descent power supply.
Just also check that the blown ferrite beads have not damage the tracks beneath them.
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here is the picture with what you should measure.
You simply need to plug the USB, nothing else
you can use any ground point on the board. the easier one to use is this one. square pad in the connector.
Thanks J4bberwock! I tested the chip as described, and on the non-working blade I do get 5V on the input, but no 3.3V on the output. Just a 0v read.  The working blade shows the correct 5V input and 3.3V output. I'm assuming this means that the AME8805 is fried. I'm certainly no good at SMD soldering, but do you think I could have this replaced by a pro? Could this failure have caused damage to any of the other components? Thanks for any other info. Hopefully I can get half my money back from the seller. Just make sure that you use a high enough wattage soldering iron and be careful not to force the AME8805 off the board or you can rip the tracks up, best way to do this kind of work is with a hot air station, most cellular phone repair people have them and they can replace the part for you in 5 minutes. |
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Definitely the AME8808 that has blown on my board, going to order some AP1115BY33-13 this week and see if they work, have checked the datasheet and definitely are pin for pin compatible.
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My one blade died, thought it was the upper fet which I replaced, but now when I connect the power supply I hear a buzzing noise from the power connector and the power supply goes off, have checked the boards for shorts and nothing I can spot, any idea's ?
maybe the 16v 220uf Capacitor. I suppose you also replaced the ferrites/0 ohm resistors that burned with the upper gate mosfet. There are very few components between the power plug and the mosfets, so they are easy to track: Plug -> ferrites -> capacitors -> mosfets You can check the 8 chips schematics on github for some help. It's almost the same as what we have on the blade. I posted a few test points you can check in this thread. It can help finding the origin of the trouble. Was a dogdy FET I replaced with, power now works, but looks like the Micro controller is fried now, does anyone have the firmware for the STM32F103RCT6 ? Could also be that regulator that you guys are talking about, will have to check that tonight. |
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My one blade died, thought it was the upper fet which I replaced, but now when I connect the power supply I hear a buzzing noise from the power connector and the power supply goes off, have checked the boards for shorts and nothing I can spot, any idea's ?
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Did anyone meassure ferrites which needs to be replaced?
Have anyone data?
Impedance:?
DC Resistance Max:?
DC Current Rating:?
The 1206 size Ferrites are 300 Ohm 100Mhz 3A, the 0805's are 300 Ohm 100Mhz 1.5A You can just use 0 Ohm resistors in their place or bridge it with 2-3mm thick of solder. I replaced mine with 120 Ohm instead of the 300 Ohm and no problems. |
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After putting in the CSD16321Q5C the stock 220uf gets very hot, just a warning to others, you might want to put a 20v or 35v cap in its place.
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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
anything else than the ferrites and fet blown? it can be helpful for some other people. As far as I can see, nothing else damaged, I did get a confirmation from gridseed that you can use 100ohm 1206 100Mhz Ferrite Bead instead of the 300ohm 1206 100Mhz bye the power plug, but they say you can't go lower than that, but I suppose if your using a good quality power supply you can just put a 0ohm resistor in the or jumper it like you guys do. As for the FETs, I have ordered : CSD16321Q5C (replaces IRFH5302) * Dual Cool CSD17556Q5B (replaces IRFH5300) * Correction these are not DualCool Which are the DualCool type, should run a lot cooler Sorry guys, just made a correction on the above post, the CSD17556 is not DualCool. Got the CSD16321Q5C on 1 blade so far, much cooler, finger does not burn now when I touch it  Will Change the CSD17556Q5B's this week and then to do the resistor mod. If I increase the resistor by say 3K, what will the heat be like on the gc3355's are heatsinks needed ? Wish I had my cnc milling machine up an running, would have converted the whole blade to water cooling. |
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My CSD16321Q5C arrives today, gonna solder them tonight and have my second blade up and running CSD17556Q5C arrive next week only, so will try them then. |
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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
anything else than the ferrites and fet blown? it can be helpful for some other people. As far as I can see, nothing else damaged, I did get a confirmation from gridseed that you can use 100ohm 1206 100Mhz Ferrite Bead instead of the 300ohm 1206 100Mhz bye the power plug, but they say you can't go lower than that, but I suppose if your using a good quality power supply you can just put a 0ohm resistor in the or jumper it like you guys do. As for the FETs, I have ordered : CSD16321Q5C (replaces IRFH5302) * Dual Cool CSD17556Q5B (replaces IRFH5300) * Correction these are not DualCool Which are the DualCool type, should run a lot cooler |
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Gridseed blade arrived last week for X-Hash, very fast delivery to South Africa, must say I am impressed !!! I don't think they even sleep, skype is always on. Thanks X-Hash !!! Attached to my old HP server, running cpuminer-gc3355 on Linux  |
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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
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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,
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