Topic: Bfl jalapeno failures and USB problems, SOLUTION FOUND (Read 5457 times)

Makes sense. With these three new jallies, I ordered the 3 wire PCIx cable so I wouldn't have to use the power supplies. Guess what didn't come :-)

Oh well, so I get to cut off the wires and hook them into my corsair. Man that thing is under a serious load right now, especially with 20gh per jally.

C

I bought two spare PSUs for my Jallys on Amazon for $8.00 each.  They work great.  BFL also sent me a replacement for the first one that died.  I just figured it was worth $16 to keep them up and running while waiting.

Bonus style points if it doesn't, but you bend the leads over like a PLCC.

The price of the coponent itself is OK here too, but the p&p is sometimes unreasonable.. :-)
Maybe we'll try the HF one, if it'll be more easy to get. Hope we can try today.

There is a fair bit of extra pad, might fit. Worth a try...

Suppose the capacitor goes from one AC pin to the DC "ground", as you say.
Then, in Europe, you won't get 120 V there. The 230 or 240 V lines aren't symmetric to the ground. When you're lucky, the capacitor is between AC neutral and DC neutral. When unlucky, you get full 240 V there.

Another possibility might be there's a "bridge" in the PSU, halving the input voltage, and its center is connected to the output neutral... This way it could produce 120 V in 240 V environment.

The LQFP package has a little bit larger outer dimension (ends of the pins to the opposite ends). So it won't fit on the PCB pattern exactly. The pins will sit on the PCB pads, but will exceed them a bit, so they can't be soldered standard way as on their regular pads.

How about the HF? The things cost 5 bucks here in the US. What's with the high euro price?

C

I think the problem is the power supplies have a capacitor going from one of the two AC pins to the DC neutral. This can be very helpful for increasing the power factor, but if the capacitor were to short then it would conduct one of the 240 volt legs to the negative line on the jally.

This 120 volts would not be a problem except for the fact that it goes to the ground of the USB line. Which then goes to your computer. If your computer's USB jacket is grounded, then 120 volts goes from wall through broken capacitor through jally through USB cable to computer to frame ground back to the utility. Boom.

Speaking of which, one should be able to replace this chip with an LQFP 48 pin one which would be a hell of a lot easier to solder. Recommended for followup.

C

Thank you very much for your report, lightfoot.
The same thing has happened to my friend's Jala. Power adapter failure, and the unit not recognized thereafter. Booting normally, LED flashing first, than steady, two LEDs for two chips... So I believe the PSU has taken the USB chip with it, as you have found and verified.
It's not quite simple to obtain a new one though. There are several types & packages of FT232, but the HQ one is not frequent at all...
Mouser wants 40 euros (!) for p&p (or I've failed to find a better offer), maybe Farnell will be more acceptable, its shipping is "only" 150% of the price of the component itself... :-))) I've left this on the owner of the cube. I myself don't have one unfortunately...

BTW, what's Miller? A sort of beer, I guess? ;-)

After a quick read thorough, my 2 cents worth.

Am sure alot of these units will have been pluged in using a US/Euro adapter.

The PSU I received is auto switching so voltage is not a problem.

I have seen many of these adapters that do NOT carry an earth/ground pin. In this case the PSU may technically fail safe but the adapter is preventing the fault path to achieve this, raising the potential between the chasis ( and USB GND) to the ground. OUCH. So the fault path becomes dependent on the USB connection to the PC, be careful plugging that baby in 

Easy solution, cut the plug off and put a local one on, seek advice on connections

Brown = Live/Active
Blue = Neutral
Green/Yellow = Earth/Ground

or

red 2 red , black 2 black and blue to bits   

Update. Sunday night, still running, no problems. Glad this works.

C

Jesus fucking Christ. You know, I think given enough time I could fix a rainy day.

Summary: This burned out jally with no USB response is fully operational. What happens is the USB FTDI232 chip burns out, and you have to replace it. For someone who has done Xbox repair this should not be hard. For someone like me who has done BGA and SMD work but not these stupid QQ chips it's a screaming pain-learning curve.

Removed the old chip with air tools at 450c with a 350F preheater under the board. Came off no problem. Put new chip on with same temps (2 mins at 450c) like a BGA cpu. Burned the fucking chip out.

Pulled it, put another chip on, 275c for 60 seconds with a 350f preheater (I buy 3 for shit like this). Chip goes on, comes up as a BITFORCE, all "J's" when I try to run diagnostics. Um, I think I need to reflow. Added solder balls, melted with the iron, cursed a lot, hit it with 300c heat for 60 seconds around the sides of the chip, and...

It COMES UP! It's a 6gh jally. It sucks, but it does run.

So I fire up the BFGMiner and it immediately screams that the chip is at 130C. Fuck again. Check the diags, S2 is at 130, S1 is at 30c. Um... Pull the heat sink. Note this one had a loose heat sink from the factory and it was banging around. Found that S2 was ripped off the board by aformentioned sink, and the pads were gone too.

Time for a lobotomy. So I went into the code, changed S2's AD channel to be S1 so the code will always read the working S1, put in a comment saying I know this sucks, but I had no choice due to bad assembly, compiled it, loaded it, attached the fan and...

It's hashing away at 6gh now. So it looks like a blown European Jally can be fixed with a $3.00 part, and a person who knows how to sweat chips on and off the board.

Go now, everyone. Fix your jallies, hash, and bring the difficulty up. I have completed this task, and if it wasn't 4am I'd say it's Miller time.

Fuck it, it's always Miller time. Off to get a cold one then to bed.

If you can, please.

C

I just checked on the dead one w/o chips. Using the usb housing as ground none of them were grounded. Do you want to know about the living?

Um I forgot. However I put a new 232 chip on, nothing. Interesting. However a question: Do you see ground on any of the 4 USB pins?

Oh and 4 chip jallies with AL heat sinks? HOT AS HELL! Put sinks on the bottom like now.

C

Ok I've been looking around and can find no info what so ever on the chips ball size. What are you using? I'm fine with spending a few bucks but can't find any info. If I'm going to be putting on 144 balls on every chip I want to do it right the first time.

Well, let's think: What could cause a short? Your chips!

If you don't want to take them off, then get a light, put it on one side of one of your chips, and look through with a loupe or glass on the other side. See if all the balls are perfect? Then do the other axis.

Try removing your chips. Yes, you're gonna reball. Let's go halfsies on a reballing stensil and table, screw it.

Myself, I have a vial of balls from ebay, since there are only so many of the things and I have watch tools I am going to try putting them all on and see if I can make it go. Line them up, then low low low air and heat to see if I can melt them. If it doesn't work I'll get a stencil.

As for the first paragraph, eh I work with heat pads which can make up the height loss. I'll try one on the dead UK board once I bring it back online.

C

Ok, I've thought about this and the chip would sit at a completely different height look at your chips and the ones BFL put on. You can see with a flashlight and bare eye underneath. Theres a small amount of space created by the solder balls. If they say perfectly flat with solder those little balls would cover a lot more area. W/o the balls it will prolly cause heat issues from 2 things the heat not being dissipated into the sink right unless you shim, and the bad contacts on the BGA can cause numerous problems like the connection occasionally bridging or burning out. I don't even know what size balls these are or if they make a template for the masses to easily reball with enough time a template may not be needed.

As for the dead jallie I think you're right about it being a short. I don't know the places to look, I've literally stared at it for ever. It's a second rev board with only one JTAG so it may not lay it out as simple. I'm not following traces on the back of the board though. If I got a nice pic and started labeling board parts would you want to fill in where you can?   

Haven't reballed, but I have taken the solder off two chips, and will try mounting them to the next jally. I think you can do it without reballing, my problem is cz main jally is not going to take more chips. I think in your case one of the chips is shorted on the 1v supply. Fix it and mine like hell :-)

C

Yes I floated the chip off like putting the ASIC on. Pre the area with some flux and heat again to flow smooth. Put new chip on, flow it onto the board. while its still hot put a little more flux and solder the leads on good. Clean up as necessary. (A short wouldn't make ya happy right?)

I think this was the hardest chip to put on yet. My forth jallie when given enough power by a 1500 Watt PSU lit the power LED for a sec and is now dead again. Hmm back to square one with out a hole in the chip this time. I want to know if anyone successfully reballed a chip yet. I don't have a problem with stealing the chips then.