Not sure. I use a nonconductive white stuff, will check at home.

Meantime I'm up to using Tektronix scopes to try and sort out the bottlenecks in some of these boards. Trying to use probes on those itty bitty chips is fun, but I have got the SCL busses identified on the power supplies and the LM75/EEPROM. Now to figure out where the signal to the chip's oscillators and/or on-chip registers are getting blocked....

Never boring.

Yup. The 2.0 requires a different microcode/IPL loaded (Fuck, I'm old) and the Titan 2.00 code doesn't include it. You can recompile the code and load it on a 2.0 Pi, but it's just. easier. to find. a 1.2 Pi.

I've done the reflow with some success, especially on the so-called taco boards, however sometimes the chip connections fail inside the die which is pretty much impossible to reflow. You do need preheat under the board, flux, bring it up to max temps, then use a real air tool at 400c to make it go. I'm sure you have a good IR preheater. And don't sneeze.

The .8v short is the one that sucks rocks; if you made a stencil then you could re-ball the die without the dead die's balls and get 2-3 dies back. Nicely done, post your progress.

Did you figure out how the level drivers for the SPI to die interface work and which ones are replacements yet? That seems to be the source of the board comes up but no dies hash, I have had some success with swapping out the top drivers, but a few still don't work.

Keep posting progress, it's how we help the community.

C

Simpler. Just use a 24 gauge wire-wrap wire and run it under the connectors. Works fine, and solves the problem without having to pull the connectors (because the same line always blows)

Just remember to tell the person to junk their Pi and get a new one because that's the root cause.

C

Not right now. I have two other projects on the bench I have to figure out first.

Hm. Is qberty2 possibly cold-soldered?

C

Is that from a real KNC bridgeboard?

C

Big problem I have in life is trying to figure out what the components on these boards *are*. I can make assumptions based on signal input/output, size, and overall position in the communications chain (for example the U204 components at the top left of the board. They are signal level converters, but finding them with a 3 character ID is a damn bitch). Likewise the crystals, the numbers on them don't seem to make much sense.

Anyone got good pointers to identifying these various components? I've pretty much fuzzed out the board, so we don't need the schematic so much as the bill of parts.

Are you sure the heat sink on the chip is making proper contact? Those studs bend in, which could cause a small gap. How are the die temps and can you feel the warmth in the heat pipes?

Sorry, focused on these weird dead boards that come up, no hash, PSU's appear. They seem to have something in common, in each case the readings from U19 (the Z17C I think) to ground on the pins are different from Neptunes (which I know work). These seem to be the level controllers to match the signals from SPI to the Neptune/Titan chips which run on a different voltage. Still have no idea what this chip is, anyone know?

If these things blow up with enough force to take out the FPGA maybe they are also taking these chips out too.

Investing way too much time in this :-) But curious.

Ok. No sense crying over spilt milk so I fixed my rig. Turned out my Pi's memory was corrupted as well, replaced that, the FPGA, power chip, etc etc etc and now I seem to be back up and running.

So I have a few boards here that identify but don't hash. I think the blowout I saw on my controller was a clue to what's going on; when the power supplies blow or the pins on the PCIe go bad when you cook the leads *and* you're running with a bigger power supply all hell can blow loose on the SPI bus. The signal bus does go through those level converters on the Titan, my guess is they are either blown open or shorted. I still don't know the part, but they seem to be the same as the ones on the Neptunes. I'll try swapping them with neppie parts and see if the board comes up.

GOOD!

Can someone see if the new owners will send over the bill of materials for a Titan? The level converters are something I can't seem to source (along with the displays), a BOM and a traceout of the board would be exceptionally useful.

Heck, I'd even tell them how to wire up the optoisolator to keep these things from blowing up.

C

Hm.

Ok, some rambling thoughts here from someone who does his best to try and fix these things. Let's start by keeping the following in mind:

1) Titans, and most bitcoin mining equipment made are not the paragons of reliability or consistency. Ok, they're crap. Total and complete crap. We bought crap. This is not consumer grade stuff, and if it was made to be that, we would never have it. Economies being what they are, people want the fastest cheapest shit you can get NOW, and the mining companies cater to this. They have to, if they don't someone else will and they go out of business.

Which is sad since a simple optoisolator circuit on the Titan would totally fix 95% of the major failures. Probably cost a dime. But not done. Oh well.

2) Given (1), this stuff blows up. Yes, it sucks, I understand that. But especially when people run things full-bore, don't keep the equipment clean, and don't keep an eye on things, they blow up. There are few safties built into this stuff, and while the builder would expect people to run them in a 70f data center people run them in fracking barns.

3) Fixing this crap is hard. Designing solutions is hard. You're talking no documentation, no manuals, no support, the people who built it either got out of business, are focused on new models, or enjoy spitting on you for stress relief. So when it does blow up, either someone steps up to try and fix it, or you're fucked.

4) Even given (3), the wide variety of ways one can screw up installs makes fixing this stuff even more fun.

And the biggie:

5) If you want people to try and fix this stuff, try not to flame them too hard. I'm sure you're frustrated, the vendor ignores you, and it might feel nice to take the stress out on someone who is trying to do something. This is complex: Too much flamage and they stop fixing things. Then the community is back to 2 and fucked.

I don't know qberty, or most people. I think it's pretty simple to see why the bridgeboards blow up: KNC did a suck job of not fusing the fucking inputs. And people run these things on mammoth power supplies that will happily source 5 volts at 200 amps into a Raspberry Pi that decided to blow up and expects 1 amp of power from a USB cable. Sure I can fix these, but if the person plugs in the same burned out Rpi with the same tank power supply the result will be the same. Foom. So now what?

Qberty took some time and actually built a new board. Cool, but as we're figuring out the problem isn't just the bridgeboard it's the lack of a fucking fuse to limit current and the fact that the Rpi's are kind of cheap and short out. So if you blow your bridgeboard and you put in a new one, and the Pi is still fucked the result will either be the same or something else on the board will blow open. Or the power supply cable will fail open.

Point is if you flame his ass too much he will send you back your .2btc and just quit. Or tell you tough and just quit. Which is bad, if we want these things to keep running we need more people to fix them. That's why I write all that technical crap in my posts, so other people can FIX them. Because Bitcoin/Litecoin/Shitcoin needs all the help it can get to succeed.

Fixing this stuff isn't simple: I just had someone's unit come in that blew a power supply so hard it cracked FETs. When I pulled the supply things looked ok so I put it on my test controller. Whereby it promptly burned out my test controller, setting me back a week while I got more damn power and FPGA chips to fix it. The thing blew up so hard it took out the supply next to it and shorted +12 right onto the SPI line. Fucking great. It's frustrating but I deal. And I tell people whenever possible to slow the things down because they blow up less at 60mh and lower. Ok, let's not go there :-)

I'd be happy to look at one of these bridgeboards, but I'm not going to flame people publicly if they're actually trying to help Titan miners. It might be a simple error, it honestly might be a bad board, it could be something on the controller or the cable or the Titans that blow the board up. See above for "anything can happen with these things". They're unpredictable, they were made that way. Because it was quick and cheap. Let's keep that in mind and relax the flamage a bit.

Goal is to keep people mining.

Ok, I have a really fun one here. Titan blew up, #4 supply shorted hard enough to break the FETs and twist the PCB board. Never seen anything quite like that, will post pics.

Removed the supply, put it on my test controller. Blew up test controller's FPGA. Great. Replaced FPGA chip, removed #5 supply as well, hooked up with no 12 volt power (oh, the 12 v PCIe is broken down to just pins due to an earlier failure I guess).

Very odd. No power supplies, but the chip temp from the LM75 *does* show up. Doesn't report as a TI. Hm.

Replaced the EERPROM chip from a dead board. Now the EEPROM comes up, I can see the supplies, but the chip will not come up to hash. Just does the voltage going nowhere thing.

Edit: It also appears to have taken out my Rpi as well, as it is not stable. #5 supply had the +12 line shorted to the spi line which put a nice fat 12v on all of the SPI components. Great, back to the drawing board.....

What a mess :-)

Just watch out for fire due to lack of fusing....

naah, you volunteered, so there we go. Forrest gets the 1%. I can't donate a bitcoin at this time, so anyone else want to step up with the rest?

I thought the original deal was .5btc?

C

Yep, that will work. WP send me your address in a PM or something. Or post it here.

They're difficult to replace due to the high solder temps required for reflow and the limited air you can get under the VRM without dropping off components. Pain in the tail however replacing the top side FETs (which are usually what short) is possible if the underlying pads aren't destroyed.

The bigger problem is if the short caused a voltage spike on the 12v rail. This can blow out other components or boards on the same supply, very annoying. But yes, i can take a look at this and see what's what.

Well that's a good question. I have a p2pool node over at the base, do I have to transfer bitcoins to the base wallet, then do a payment to all miners of .2, then the others do the rest of the .3 then shit gets done or should we all send it to one person's wallet who can do the whole .05?

I'm fine either way.

C

Fish and Chips?