Topic: Hacking a BFL Jalapeno to 32GH and beyond....(???) - page 11. (Read 54325 times)

Ahh I see, they cut the board so close to those test points the silkscreen of gnd, 1v etc is missing.

OK at the test points I have: 1.01V, 0.0001V, 0V, 13.1V
should I have 5v?

Resistance between ground and:
1v = 41ohm
3.3v = 0.20 ohm
5v = 2.9k ohm
12V = 2k ohm

It's hard to tell if this is the burnt out u15 chip causing the short or something else as well causing this.
If Mr Teal thinks it might be hard to diagnose then it might not be worth removing u15 and RMA'ing instead.

Thanks C,
I'll test it when I get home tonight.
'spose i'll asses from there and see if I want to try fixing it myself or not.

It's not too bad. Grab the schematics by googling for sc-mainboard-1.0, it's a PDF from BFL. Once opened take a look at the board layout. On the opposite side from the power plug (top side) you will see a square hole, then a space, then five more holes. Right by the JTAG port.

Those are the voltage test points. They are:

ground     1-volt     3.3-volts    5.0-volts     12 volts.

All reference to ground. See what you find with the board plugged in.

C

I just get the red light near the power connector, none of the other LED's light up at the front or back.

I have a multimeter to test with. I just need to know where to test. I haven't had a chance to look at the board layout and see what is what.
I'ts certainly the most tightly packed board I have ever had to look at.

Ah. So what I see when I tested a shorted jally (and I have shorted the danger board a *lot* as of late) is the crow-baring of the cheap-o BFL power supply and not a failure of the 1 volt supply to come up into a short. That is interesting, I wonder how much power it sourced before blowing up. Probably a lot. :-)

Ok, then my protocol of testing a newly balled jally with a BFL supply in all cases is sound. That's good to know.

C

Despite my intentions to do so, I didn't (install a fuse) and thats exactly what happened to the board coming your way.

Hm, yep that's the 4 amp 3.3 volt power supply. Out of curiosity what happens when you plug it in now?

Do you have a volt meter and know how to use it? I'd be really curious to see if the 1 volt power line is up; it feeds off the 12 volt supply line. If that's working and the 3.3 volt short could be cleared you could power the board up with a small bench supply and it might work again. But man that is a serious hack.

Speaking of serious hacks, I have a board coming in with a blown set of 1 volt FETs. I'm going to try powering it off the danger board with jumper wires; technically it might work. Then again the voltage drop might be too much but what the heck?

:-) Keeps me out of trouble.

C

Thanks for the offer. I'm in Australia though so probably not worth it for me.
I think u15 blew because I recently changed to an ATX power supply rather than the power brick (all in effort to prevent something like this from happening.)
The sparks came as soon as I un-plugged and re-plugged in the USB cable while trying to get rid of "unresponsive asic" messages in cgminer.
For next time I'm considering wiring in a 30v 6A Poly switch that I have here or maybe a fuse.

Thanks everyone else for the suggestions. I don't have a current limited power supply so this might be a bit too hard to fix myself.
My main issue now is if BFL will try and fix it before sending me a new one. If so they might see that I reflashed to get to 7.8gh/s

Freeze it with spray (or compressed air upside-down) and see where it becomes hot - is another method.

I wish I could say yes. I believe when I originally replaced it just powered up for a second. It blew again or something else when a real PSU was used. I think I pulled a pad off when removing it a second time. So I removed the chips and will list on eBay as a dead jallie soon..... Sorry

Yup. However the 3.3 volt supply on a jalapeno is really pretty small. Even the 1 volt supply will just crowbar and die if shorted (verified on the danger board); what blows things up in the FET world is when the FETs short due to overheat on high loads. Then if you feed it from an unlimited 12 volt supply (as opposed to the little supplies BFL sends) then the weakest component will explode.

That's why I have been recommending putting a 7 amp fuse in series with your jally when running it on 300-800 watt supplies. 12 volts at 7 amps will do minor things. 12 volts at 50 amps will do a bit more....

Having bench top power supplies is a godsend; I have a pair of them myself and can feed all three voltages to a board. Oddly enough I am getting a board with blown FETs on it, I'm debating checking the 1 volt rail, clearing the failures, and trying to power it off the danger board's 1 volt supply. A double-headed jalapeno. :-)

It keeps my mind working.

C

Remove the chip again, and check the resistance on the 3.3V rail. If it's below about 10 ohms or so, something is shorted and that's what keeps blowing the ST1S10.

Shorts on a main power rail like that are a huge PITA to debug. Depending on what you have available, there's a couple ways to find out what the issue is. The easiest way I know is to hook a lab supply at 3.3V up to 3.3V rail and turn the current limiting down. Grab an IR camera, and turn up the current until you see a hot spot. You can do the same with an IR thermometer, but it's more time consuming. A finger work too, but you need get the problem a lot hotter that way, and if it's something that's a QFN or one of the ASICs you might never notice it get hotter.

Without a current limited lab supply, it becomes more of a crapshoot. It's probably not worth trying to debug yourself if that's the case.

You blew up U15 as well? Hm, interesting; wonder why that is failing.

I think that is the 3.3 volt supply line, if you want to send it over I can take a look at it. I'm sure though they will honor the RMA. Drug, did swapping that chip fix it?

C

Bugga, I just blew a hole in the exact same chip in the exact same spot. I thought it was new years eve fireworks again.
Power supply tests ok though. the thing powers up with one red led near the power connector. The red leds on the back and front don't light up anymore.

Torn between sending back as an RMA, or having a go at replacing the chip myself.

Well, it looks like Danger labs is going for the gold. I just picked up six of these, will distribute as follows:

Jally 1: 6 chip to 8 chips (+2) Looks like the water cooling block may come in handy.
Jally 2: 5 chips to 7 chips (+2)
Jally 3: 5 chip (this is the bad board one) to 7 chips (+2). Might as well set it alight as well.

This will cover my three dead chips; I'll use my last good chip for a friend's jally, giving him a 12gh unit that can be used or sold without super cooling. My reballs I'll put on the danger board if I can, what's the worst that can happen?

I am going so straight to hell here. But it's all for... research.

Right.

Crap, I just realized something: I have one other chip, and one of my slots is bad. So I can only do four. UG. Will request update, if seller does not agree will honor 6 chip request.


Same here. At this point it's pointless to get the cable; I'm already at full power here. I guess I can just ask BFL to send me a chip or something instead. Or my money back. :-)

C

BlackFriday Jally Update 2:

So finished up my splicing and dicing on New Years Eve. I decided to make 4 3-chip Jally's so I could salvage their resale value:
Here's a screen shot of the final output. The two doing 11+ are the 2 chip Jallys that I added a chip to.


Of the 4 received, only 1 had the original old style chips (notice the one running @ 69C, that's the one). The remainder having a level plane all made good contact with the stock heat sink. I decided to go with arctic silver alumina for thermal compound and after flipping the fan and adding thermal compound beneath the bottom of the board and the aluminum/zinc back plate, all of my temps are good.

Here's a shot of the 8 hole plate I mentioned on the first post:


It was nice to see the boards with the newer style chips. I don't see any immediate advantage of the 292 firmware other than you can add chips without flashing. Here's a shot of one of the three chip boards I received, I received two 3 chip and 2 two chip models.




And I didn't go crazy so I have 13 chips left.. Look for a thread under Computer Hardware if you want them.

https://bitcointalk.org/index.php?topic=395129.new#new

PS: I'd ordered two PCI-E to 3 Plug custom power cables when I placed my order. They were not in the box. Logged back into BFL's site and checked my invoice, and it clearly shows I paid $29.98 for the cables and also indicates that they were shipped. I wrote an inquiry to [email protected], but to date have not received a reply.

Interesting read.

Feel.free to drop some bitcoins in the research bowl or send repairs my way. However one may be able to mount a chip without reballing. My error was working with these older chips.

We learn by doing. And people have donated time coin and chips so it all works out...

Just to let you know, watching and reading with great interest, you are cutting edge on info on homebrew projects like this, your pain - my gain

Found my old toaster oven in storage and my industrial heat gun (paint removal- looks like a hair dryer), also my old laser temperature tool. May give it a whirl on some stuff.

Reballing seems to be mandatory from your experience tho, was hoping to avoid all that.

Well, in the "lessons cost bitcoin" category I finally figured out why I have been failing in mounting this chip on the danger board.

This is one of the "early model" chips that are on a tiny carrier and do not have a logo. Got three of them for .12btc a few weeks ago. And one of them I tried to mount on the danger board. But each time I tried to clean it up and put it down, the chip would short the 1 volt supply line. Every time. Over and over. I thought I was a complete loser.

Then I tried to put another one down on a totally good board. Pre-heated, aligned the balls perfectly, applied the heat to the top, after 30 seconds looked in and saw a tiny solder ball on the chip carrier.

CRUD! Now I know what has been happening: Instead of bonding the chip to the carrier board with high temperature solder, they used normal solder. Which means the heat from my air gun would heat the chip and not the board under it and as a result the solder on the chip itself would short under it on the carrier.

CRUD AGAIN! That's why this other chip was shorting. And why this chip I was putting on didn't even mount to the board, just made a total mess of things. So I removed the solder on the board, swore for awhile, and put the chip away.

I'll sell all three of them for .04 btc, as either souvenirs or if you think you can get them going. It's just the cost of doing research, but I would *HIGHLY* recommend that you do not buy old style chips unless you have a full reflow oven and pace placement tool.

Lesson learned. One good chip left, two chips in need of reballing. So I should be able to put this last chip on the 5 chip board, making both 6 chip boards, then if I can get these other chips reflowed I'll try putting them on the danger board. :-)

C