Topic: Hacking a BFL Jalapeno to 32GH and beyond....(???) - page 23. (Read 54329 times)

Josh, admittedly I have not been your biggest fan but I am glad you participate in this thread.
Thanks for your comments and being helpful.

Best Regards

The chips come off nice and easy with hot air or IR as well.  You'll have to re-ball them, but I've pulled the chips off with a hot air wand almost completely intact ball wise.  With some focused IR heating, you could probably get the chips off completely intact.

Darn, still nothing, even at 450c for 1.5 minutes. Chip must either be dead or seriously confused.

Mining again, will leave it on and alone for now. Dead chip still on board, will watch temps and power draw to see if anything changes.

Oh well, you have the good days and the bad... :-).

C

Hm, darn another setback.

Got the two chips today and have tried putting them on. Chip 6 is pulling power but is not coming online; normally that means it hasn't completely flowed but I have re-heated it several times, each time with between 390 and 420c from the wand for 1.5 minutes. That should be more than enough, and was enough to get the last chip going.

And to add annoyance to injury after one heating all six lights *did* come on, then on the next reboot the new one went off. DAMN that means the chip is good, but not communicating. I'll have to think for a bit.

Crud. The chip is square, I'm going to have to think about this one for awhile before going further. Now it's hashing at 19gh, but pulling 150 watts total (computer plus rig) so the chip is drawing power. Drat.

Chip #7 went on the board, but floated down so it was off center. Had to take it off, and clean up the board from several solder fails. Drat again.

Need to pull the sink again to install the fan; maybe I'll try one more time to heat chip 6, then call it a day for today. Not sure why it isn't working, darn it :-)

Well, I know why, one of the control balls is not coming down. I wonder which one...

C

Yes, put heatsinks and a fan on the MOSFETs if you are pushing it that hard.  Sorry, I would have mentioned that, but I just assumed people would cool those automatically.

Check out my other thread at https://bitcointalksearch.org/topic/hacking-a-bfl-jalapeno-to-32gh-and-beyond-336782

Note I'm tracking a possible problem with running a full set of 8. I would recommend not going past 6 without cooling those FETs, 7 tip tops.

C

Hey Lightfoot, what temps do you run your 968 at?  I have a 968a and might try this.

I have never worked with tools like these. But adding 4 or 5 chips to a Jally sounds so nice. I supposed I would just blow it up... but it would be fun right?

Update: Looks like the latest ebay seller is sold out. Apparently I'm good advertising. :-)

Also to note: Going to speed 9 actually slowed the unit down: The weakest chips went down to 2.2gh/s and temps went up. So I moved things back to speed 7 and speeds are back at 19gh.

Sounds good. I think it's worth it, and I'll be interested in hearing how you do with an IR unit. Post what kind of tool you're using and the temps that work out.

Still waiting for my chips. Looked at it again last night, still hashing solid at 19gh. Oddly enough though most of the chips are at 3.5-3.8gh, with only one at 4.2+. So there might either be a residual heat issue, or I have the testing up a bit too high. I should also try speed=9 to see if I can bring out more speed at the expense of more heat...

C

Thanks for the inspiration!

Just picked up 9 chips... I have an infrared solder station for mostly phone work... sim cards etc...

3 jalapenos will be hacked!! Starting with my dud... 6.3gh (after firmware flash and tweaking)... probably going to pull both old chips off and put 4 new on. I'll keep you posted.

This should be fun!

Bad news: My offer from the previous Ebay vendor for the two chips was declined. Drat.

However I placed an order with a different vendor and got the two chips no problem. So now I can go to at least seven, should have them by Saturday for an install. I'm just going to put them in the last two spaces (one corner, one middle of row) that I have not soldered chips and take a good long look at the last spot. If it looks ok then I'll try getting one more chip and going for a full 8.

Here's the vendor link: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=151168046486. Looks good, good reputation, I'd say order 4 chips at a time and see how it goes.

The power supply arrived, and temps on my rig with the heat sink have been a nice reasonable 60c. So I have room to expand both in terms of power and in terms of cooling capacity.

Next stop: 28gh!

Well, in the "fail" category I think I damaged this first chip beyond use.

This evening I took it outside and removed the existing solder balls with the Radio Shack monster temp controlled iron, set at 725F with a lot of rosin flux and traditional solder removal wick (copper braid). That did the trick far better than hot air; and I got the balls off in quick order.

Rinsed it with 91% isopropyl and took a look at the pads under a 6x loupe. Several of them are missing, along the edge, and I'm guessing that might be where the communications lines were. Which is worse than losing a pad or two in the power side. Anyway this picture shows it, the dot is on the other side of the chip, upper right.



Worst case I'll get one more chip. But I don't think I will risk this chip on the board now.

C

Done. I'd be interested in trying out a better heat sink solution on either/both sides.

In the meantime placed the order for two more chips, I'll put chip 6 on in the next day or two.

C

Yeah, we have a new heatsink that goes on the bottom of the units that are shipping with newer units that replaces the flat reinforcement backplate.

Email me one of your order numbers and I will see if I can get a heatsink sent out to you so you can give it a test.

Ah, ok, haven't seen one of those personally. Is there a part number or something I can order that sink from somewhere? Or something similar aftermarket?

I will say that checking it this morning that the copper heat sink I have on the bottom is contributing a *lot* to keeping the board cool-ish. Heat can go either way, and a good sink on the bottom seems to work well at 5.

As for the warrantly, yeah this is way beyond "I just opened it to peek". If it blows up it blows up. I (and anyone else trying this) can deal with that. :-)

Well....

What I used was an aoyue 968 rework station. It's basically a pretty nice soldering iron and an air wand that can put out air at a specific temperature and flow rate. Costs about $160 on Amazon. I bought it a few years ago to fix SMD components on 90's era electric car controllers, think 50kw IGBT drivers that explode and need to be rebuilt.

http://www.amazon.com/Updated-Aoyue-Digital-Soldering-absorber/dp/B006FA481G/ref=sr_1_fkmr1_2?ie=UTF8&qid=1384876991&sr=8-2-fkmr1&keywords=aoyue+962

Cripes, you could probably use this:

http://www.amazon.com/REWORK-SOLDERING-IRON-STATION-handles/dp/B004ZB9D4O/ref=sr_1_24?ie=UTF8&qid=1384877176&sr=8-24&keywords=aoyue

In addition I have an Aoyue pre-heater thing which basically puts out a fairly constant amount of heat and holds the board.

http://www.amazon.com/Aoyue-853A-Infrared-Preheating-Station/dp/B000PGPU7W/ref=sr_1_1?ie=UTF8&qid=1384877226&sr=8-1&keywords=aoyue+preheater

For $20 more you can get a probe. Wow! Modern technology.

To be honest, it's not too hard. You need to put liquid flux on the board (use the no-cleanup flux, try to get some tacky stuff) then put the board on the preheater and bolt it down. Now spend a *LOT* of time with an eye loupe (4x) fingers, and a set of tweezers to put the chip on the board so that:

• The chip dot matches the dot slik-screened on the board. That's um. critical
• The chip is perfectly centered within the silk-screened square. I mean perfect. As in you can just barely see all four outlines around it.

Then you turn on the heat and check the chip again. I brought my pre-heater to 300F because Aoyue assumed I was stupid and didn't use celsius on the preheater. Oh well, check to see if yours is C or F, there is a difference. :-)

Then you get your stopwatch. And time things. After 4 minutes or so fire up your 962. Bring it's temp to flow level 5 and temp of 402C. Yes, that is hot as hell. Yes, it bothers me too. Yes, that's life. 250-300C doesn't do crap.

Check the chip again. It probably moved. If not good. Note the preheat has activated the flux.

Now hit the chip with the heat. I use the round nozzle that is about 80% the diameter of the chip. Whatever. The square one sucks. Put the nozzle over the chip and bring it down over 10 seconds to the point where it is right over the chip. Start the watch.

After 30 seconds I start moving around the edges of the chip with the nozzle. Blow straight down, if the chip blows off you're fucked-ish.

Watch the chip. It should do a little move when the solder melts and it aligns itself. Keep the heat on it.

Do heat for 60-90 seconds. If the board catches fire you did it too long. I felt horrified I needed that much heat but I haven't blown a chip yet. Yet.

Remove the heat, then turn off the bottom preheater. Wait a minute or two for the solder to cool. Then take the board off the preheater, burn your fingers, put on gloves, and walk around with it to cool it down.

Look at the chip. If it's not square within the 4 lines on the board you really blew it. It probably is.

When room temp, plug it into the Jally that you have already flashed with 1.2.9 with the LITTLE_SINGLE definition and made sure it WORKED and see what happens.

If 3 LEDs pop on the back along with the power led, power down immediately. You win.

If not, reheat and try again. Go a bit longer with the heat.

If the front LED flashes, power down, you shorted the 1 volt power supply. Thank BFL for the crowbar detection and come back to this thread. Or re-heat the board again, it might not have soldered correctly.

Anyway if it lit 3 LEDs then put on the heat sink, fire it up and check out the performance. Should be 12gh. Then keep adding chips until something melts.

C

The same heatsink that comes on 60 GH/s long boards are the ones I'm referring to.

My question is how in the hell did you solder the chips on the board? I can do small soldering, but how hard is it really?