Perhaps. I've run into two leaking units so far but when I checked one of them out under a loupe I saw that the pump housing itself inside of the little lid had a tiny hair crack in it (you could see the bubbles coming out). There's a pic a few pages back. I tried contacting the Cool Air people, but didn't get much of a response.

Good question. Does anyone know if the CPU hot-rodders run into leaking water systems? I *do* remember that Apple did it on one of their systems, then stopped doing it due to leaks. G5's if I recall. Hm.

Cooling is fun: One problem is you need to have a temperature differential as well as some sort of fluid flow in order to cool anything. 70 degree air flowing across a heat sink on a 200F chip will cool far more than 100F air going over the same sink. It's not a 1-1 linear thing, it's a logarithmic thing.

I've talked to people who ran them in >100F rooms and were wondering why they were temperature-faulting. Heat's a bitch, no doubt and these miners are generating amazing levels of it in very small spaces. If the room is warm then less heat will transfer which results in hotter fluid. Heat the fluid too hot and it will expand. Expands too much and stuff will get interesting (though I would expect the pump to plate rubber gasket to leak before the radiator blows up). Might be worth a test with a blowtorch on one of my old sedion water coolers from the Chili days....

Another issue is air/water flow rates. Fans and pumps are weird, they too move geometrically more air the faster they rotate. Which means if you lower the voltage and fan speed by a bit, you get a lot less airflow (swept area times pitch and stuff like that). Bring the fan speed up too high and you will have cavitation issues as the fan blades literally "stall" in the air.

And then it's always better to pull a fluid (air is a fluid) through a radiator instead of pushing it through. When you push you create little vortices all over the place that impede the flow of heat from the radiator/heat sink into the air.

I remember when I was running water cooling on my 8 chip jally I was puzzled that when I ran the Corsair water pump at full speed the unit got *hotter* by a good bit. Checking the temps I saw that water was flowing too quickly over the heat sink in the pump, and wasn't picking up the heat. Slowing it to medium speed worked best, slow speed didn't work as well (but was still better than fast).

One thing I did see: When I ran two Monarchs (mine and another person's) on a single 750 watt supply (pulling 800 or so watts. Oh well), they were both running much hotter than they were when I ran each one on it's own 500 watt supply. Checking I noticed the front fan air flow was a lot less, and the radiator were hotter. I checked the voltage at the supply and saw that it was 11.2 volts instead of 12.

*That* is interesting. Technically you can run a Monarch at <11 volts but the fans and pumps will now run a lot slower. Lower RPMs on the fans means a lot less airflow. It's possible that's part of the problem.

I haven't been thinking much about this, as my main thought was on keeping the FETs cool. I'll fiddle with this a bit over the weekend. Hm....

*Nod*. What kind of symptoms do you see with the overheat? Can you post a picture of the one that's doing it?

Actually you still have that temp sensor thing. Check on the back of the unit in that square of space behind each chip and tell me what the temp is. That's the temp of the back of the chip coming through the board and should be pretty accurate. Also check the temp on the top of the radiator manifold, point it at the inlet hose and the return hose, that tells us the radiator efficiency.

I'll do the same once I wake up and get some coffee into me.

Quick update: Fixed a few more Monarchs, that's good. When a FET shorts, it seems to immediately disrupt the 6 phase power supply output and shuts down the board so it doesn't burn anything badly. Then since it is shorted, a power supply will simply crowbar on startup. Makes sense.

I've got a few more coming in this weekend for repairs, so I should be busy early next week. If they have the FETs shorted it should be an easy fix to swap them out and get them back on the road again.

I just found out that it looks like BFL is no longer under receivership, which means that they will be able to get back to doing RMAs and shipping again. Good.

I'll have to think about what this means in the long run, but in the meantime the Monarchs that are in the shipping pipeline to be repaired will be fixed under the current "donate the money to a food bank" program. Maybe I'll extend it till next week while they get on their feet or something, I'm sure they are probably busy, so if you have a problematic Monarch that needs repair let me know and I'll take a look at it.

Actually no one knows exactly what the heck gravity *is*. Think about it, it's not strong force, nor the electro-weak force. It makes little to no sense unless it's a force we are feeling from the higher dimensions of string theory.

Gravity is very odd.

The big question now is this: If I am a contractor for Microsoft can I select to be paid in bitcoin?

*that* is where things go from simple payment transfer thing to real "money".

*nod* Acknowledged.

Terms of repair are that Ognasty and/or Nastymining donates the amount they would have paid me for the repairs to a local food bank of your choice. I'll get to work on them when they come in and post the status and fun pics over in the hacking monarchs thread.

I can get the time off my 16s Elgin pocket watch in a fraction of the time it takes me to fire up a phone. As to being an ornament, yeah it's the one bit of jewelery I do wear, so I splurge.

Don't really wear wrist watches, but a 21600 movement will probably keep pretty good time. I'd service it, sounds nice. Wonder if they would make one in 14k gold...

I find it weird that people who use bitcoins, which are generated in a purely random method, can't get the point that it is impossible to beat the odds on gambling games. If the house has an edge, they will "win". The rate at which they win is based on that statistical edge, and it's different for every game.

In the real world, it's best to play balanced games with a minimal house edge. Craps is a good example: If they load the dice somehow you can simply play the don't pass/don't come and win over the house. Frankly speaking it's impossible for the house to cheat (the only reason the house maintains an edge against the don't bettor is because a 12 is a push, not a payout on a come-out roll. That's literally it).

However electronically someone can rig the program regardless of the bettor, so electronic games can't be inherently balanced.

Anyway, moral is if you gamble and are not the house you will lose. Always. That is why Vegas is built with all those pretty buildings and fountains.

Just like a block will drop every 10 minutes.

I believe reality exists.

Everything I could think of.

Lowest possible voltage with resistor changes (I think it came out to .7v or so), clock speed 0, no fans at all, and replaced all the FETs with much higher efficiency/better matched ones. I didn't screw with the FET clocking frequencies, but I did get rid of all that heat. (what did I do, I think it was going to 1-2 high side FETs and 2 low side FETs. If there was heat, I was working on it.

It was a little putt-putt, but I did manage to get it down below the 3w/gh barrier.

When I downclocked the Chili with your code, I think I remember it being closer to a bit under 4w/gh at a speed of about 30gh. Since we never had the real code I couldn't futz with it more to bring voltages down to the bottom range.

C

How efficient are they again with the low power flash? I disassembled my Chili awhile back, but now that it's cold upstairs I could use some more heat.

The turbo jallies did 5w/gh, the Single/60's did 4, a super low power and clock single can do close to 2w/gh. What's the current and speed for a Chili (running at full 40gh speed it was exceptionally inefficient but that didn't matter last winter).

Well, after getting some parts and working with the oscilliscope I think I can see what the problem is with the left side of the now-air-cooled Monarch. It was burning FETs, but what was weird is that the *bottom* side FETs were being burned. As in smoke. But it still could put out power to the hashing engines. Weird.

So I took off the choke to isolate it from the other supplies thinking they were backfeeding or something. Still boom. Pulled the top side FET and the bottom ones, they were not shorted. Put them back in, smoke.

Then I realized what was going on: I pulled the FETs again, cranked out the scope and looked at the signals on the gates of the FETs on the other channels. With the choke out the left side was in "hiccup" mode, where it sends a brief pulse to the FETs and looks for the current across the chokes. With one choke out you wouldn't see the current, so the system would stay in the "pulse the FETs each second". The low side and high side FETs for channels 1,2,4,5,6 were all reasonable, hiccup, hiccup.

The low side of channel 3 was also ok. However the high side was locked on. Solid 5 volts.

BINGO. That was it. The high side FET was always conducting power to the rail, so when the low side FETs closed they closed into a short, then opened from a short. The top side FET was always closed, so switching losses were none. The low side was switching, and thus burning up.

Reason? The FET driver for channel 3 was where the leak hit. It was soaked, shorted, and now was holding the high side on. Yep, that will do it.

The problem is those drivers are QFN packages. Which means that they have to be perfectly flat against the board, and a hair's difference in orientation is enough for them to fail. They totally suck and I hate placing the bigger ones which I can align using sight. These are tiny things, only 8 pads total.

But at least I know what's going on. And I can make a guess that if someone has a Monarch that had a leaking water block and is having overheats in the FET areas, they might not need to swap the FETs, but the associated FET channel driver.

I'll try swapping it over the weekend. Ug, I hate QFN. And with this much copper it's going to be FUN to preheat that region enough that I can get surface tension to mount those chips. I hat QFN, I really, really do.

But if I do manage to place it, the side should come back up. We'll see.

Hm. Looks like a 12 volt power filtering cap. Kind of interesting, might make one of the chips noisy, but probably not enough to sink the board. Let's see what happens.

C

Wait... They shipped it without a key capacitor? Can you post a pic?

I love mining vendors...

Sorry to hear that, want to send it over for a look-see? :-)

C

I'll try to take one over the weekend. The unit is back together and hashing.

Very interesting tidbit: It runs a bit hotter/faster than mine (730gh vs. 700) and I noticed it cut out while mining. When it did I heard the "USB device disconnect and reconnect" sound which was very unusual.

Researched: I'm running both miners on Corsair CX500 supplies, which are being pushed to the edge. Apparently the extra draw on this unit is just pushing it over on the CX, which causes a power sag after a few hours.

It's on a CX750M now, seems to be happier. I also noticed the fans are running a bit faster, so it was probably pulling the 12 volt rail below 11 volts, which means "on the edge dude". So if you have a Monarch on a CX500 class power supply and it's dropping off after a few hours try a bigger power supply.

Back to work. And back to DigiKey for an order of the low side FETs for this other board. Might also throw in a FET driver as well. Still not sure why it is back-feeding power through the low side FETs on channel 3 only, really really weird.

C

Second one just came in from England. Very interesting, didn't work on arrival, would power up but did not hash. Running Chiliflash on it to do a ZCX showed the board as running but with 0 chips.

Got it in, powered up. Same situation. Checked the voltages at the FET chokes: .6 volts, solid as a rock. Chips were cold on the back. So something was wrong.

Removed the back heat sink and noted the insulator had slipped a bit. Put it back on with the same old heat sink compound, fired the board up. All engines showed up, 750gh potential.

Looks like what happened is the heat sink shifted slightly or something and was shorting out the 1.2 volt power supply to the Monarch chips. Like the Singles, the Monarchs appear to have at least two power supplies, one for the hashing engines (the big .6 volt ones) and one for the hotel circuits since you can't do signal switching on .6v.

Anyway, fired it up and it started hashing but the back of the board under the monarch chip started to get hot. Bad thermal coupling. Pulled the water block again, cleaned the chip and block with 95% isopropyl and then the 1/2 cleaning stuff for heat sinks from Radio shack and put on a thin later of AS5. Put block on, GENTLY screwed down the screws in a cris-cross pattern to even out the torque, and fired it up. 30c on each side, got the thermal interconnection.

Seems to run, ran for 15 minutes at 700gh. Will once again screw with it some more tomorrow.

So if you have a Monarch that isn't running, check the right side water block. It might be shorting a power line.

Good luck and mine like hell.

Update: Two Monarch have come in for servicing under the feed a homeless person program. And it looks like people will be fed this T-day. Good.

The first one was a 500gh Monarch that had the coolant leak out of it and was shorting out power supplies. Blown FETs as discussed. I've tried to put on new little metal ones, but I am running into three problems:

1) These boards are *heavy*. As in so much copper that they literally dissipate heat from my air tools faster than I can put it down. Even with a full 380F of pre-heat with a 15 minute preheat time *and* pulling off the back heat sink *and* using Kesterel liquid flux *AND* running my heat want at 425C I can barely get the metal FETs off.

2) I haven't figured out quite how to put them back on; the problem is the gate and source pins are *under* the FET and heating through those FETs with this much heat isn't the best of ideas. I might need a bigger preheater.

3) Did I mention these boards are heavy?

So I did what I usually do: I tried something else. BFL left on the old T-MAX pins for the bigger more traditional FETs, so I went to the Digi-Key cupboard and gave some a try.

I used two types of high frequency FETs on the Jalapenos: 052NE3LS types and CSD17506 types. The 17507s that were typically used had high gate capacitance, and running them in parallel was kind of a bad idea. 17506's and 052's have much lower capacitance, with the 052's trading some gate values for more power handling.

Bad idea here: Those Intersil drivers are running the FETs at way higher frequencies for power balancig. Gate float, blew the 052's. Boom.

Next up: 17506's. Put them on and even though they have lower on current max values they spend most of their time in transition switching and can get in and out of the death zone much faster. They don't even get *WARM* for Christ's sake.

So running 6 of them on the right side chip is giving me 275gh at 28c. Very cool, very smooth, running well. The left side is still shorted from the water damage, need to work on that a bit more to see what's up.

Now you may be thinking "How is he cooling the chip with a broken water block". Well...

BWAHAHAHAHAHA!!!!!!!!!



Yep. That's an old Single/50 heat sink on a Monarch with a Single fan on a stand-off. I actually used the little plate on the back as a gauge, went into the shed, and used the drill press to drill four holes around the edge, then tapped them with the 3mm tap. Then mounted it to the chip with AS5 heat sink compound and screwed it in the back with screws using the little springs to maintain tension without cracking the chip. The other side doesn't need a sink because the power FETs are not working (and three are removed).

Yep. It works. The back of the board behind the chip is reading a bit warm at 50c, but the heat sink is also reading 50c which means it's transferring heat optimally. And oddly enough it works, I haven't run it for more than 30 minutes but it is quite thermally stable.

I'm going to give Cool-IT another few days to respond, then try fixing the leak by potting the water block inside the housing. That should do it since the pressures are low, but it's water, so who knows.

More later. Moral: They can be fixed. Now you know how.

Might be a good idea, although I just burned my finger on a FET. On the positive side I have .598 volts on the chip now, however at least one of the six FETs is not placed right (sparked due to improper solder joint on the inside pins) and another one was drawing more current than it should.

Still, power is back on one side, we have control. I'll put this to bed now and look at it tomorrow, but these FETs are way more difficult to reflow solder than TO series parts. I might have to flux both the board and the fet pins on the inside to get enough heat transfer, and even that might not be enough.

I might need a full blast IR preheater that can take the board to molten Pb free temps. Time to check Ebay, anyone else got a good recommendation for a rework heater/reflow unit?

These are seriously high heat transfer components. Oh well, what better way to learn?

Ok. Well I got the new FETs in and decided to take the old ones off this board. Symptom was a .3 ohm resistance on the 12 volt line instead of the normal 300 or so ohms.

Started pulling FETs, then found they were not coming off. Fuck these things are small. Too small for my normal picker, I'm going to need a special nozzle. Then I realized my pre-heater was broken.

*grumble* Took pre-heater apart, wire had broken at the phenolic junction between normal wires and the nichrome type wire in the heater. Fixed it, back in business.

Here's a little thought if you think you can burn these FETs off with just hot air: Forget it. In order to remove them without damaging the board, you have to take the board to 380F pre-heat, then sit on them at 450c air for *30* seconds each. Say what you want about the board, but man does it pull HEAT away from these FETs.

Started pulling, did the left 6 and no change to the resistance. 7-10 same thing, started feeling really grumpt because I have to PUT THESE BACK! Then I did #11. Instantly resistance went to 300 ohms. And the underside of the FET was bad. Looks like I found the bad one.

Now to let things cool, then put on new fets tomorrow. I'm going to need flux for this one, these are going to be hell to solder back on. But do-able, and I have now proven that FET shorts are what shut down power supplies.

On ward. We're getting there. By the way if anyone else wants to follow along give it a go!

C