HOTAS Warthog users be ware of potential short circuit

[Alex_rcpilot]

We've just had a Warthog stick (right hand) resurrected from an earlier incident. The fellow guy discribed what had happend as "a little puff of white smoke" before the device went dead.

 

From the picture of the circuit board which he took after disassembling the unit, a charred component could be seen sitting next to the VBUS pad of the USB cord. It could be a 500mA fuse or a filtering inductor which was destoried by overcurrent.

 

As he recalled later, he was mounting the unit to a steel support on the ground when this happend. The smoke was seen right after he tried tightening the first screw. With this piece of clue, the cause of the problem became apparent:

 

A. The PSU of his computer wasn't perfectly grounded, and there's potential difference between the power system of the PC and the earth;

 

B. Inside the HOTAS Warthog, the GND net could be connected directly to the metal case for better EMC performance or whatever;

 

C. The steel support on which the stick was mounted happend to be grouned to the earth;

 

D. A circuit formed along the USB Cable, HOTAS, Screw, steel support and the earth, fuelled by the computer's PSU, whose energy eventually breached the weakest spot.

 

After replacing the damaged component with an inductor, the unit came back to life.

 

 

Since poor grounding and even strong statics is very common among ordinary computer PSU's, here are some precautions to prevent similar things from happening to your sticks:

 

For the sake of every device connected to your computer, not just the stick, properly ground your PSU if possible;

 

Don't use conductive material to mount the stick unless you have to;

 

If metal has to be used, break the circuit by inserting insulation between mounting structures;

 

The stick's metal surface IS the ground wire of your computer, it's an exposed part of a circuit. So prevent any contact from nearby conductors or electric static carriers. Carpet users might have already felt the pain.

Edited January 23, 2011 by Alex_rcpilot

[Slammin]

That really sounds like a situation that could be more dangerous to human life than just the peripherals connected to the computer. If the difference of potential between earth ground and the casing on the PC is enough to fry components, then I'd also be very worried about a fire.

[WynnTTr]

Thought that would be rule #1 when handling components - make sure you're perfectly grounded. I remember in my early days frying a couple of mobos and a spanking new Voodoo card learning the hard way.

[Slammin]

Static electricity is one thing, but actual AC current flowing is a totally different problem and current flow is what you will get when two grounds are not equal. The difference can be enough to fry things, start a fire and in some cases, kill you.

 

The OP mentions the Hog in this case, but the Hog had absolutely nothing to do with anything other than being the victim of a PC that isn't grounded. As soon as you plug the Hog into the PC, the Hog is grounded as long as the PC is already grounded.

 

The only warning to take from this thread is one that applies to any device you plug into a wall socket. Make sure things are properly grounded, and on the same ground!

[WynnTTr]

Static electricity is one thing, but actual AC current flowing is a totally different problem and current flow is what you will get when two grounds are not equal. The difference can be enough to fry things, start a fire and in some cases, kill you.

 

The OP mentions the Hog in this case, but the Hog had absolutely nothing to do with anything other than being the victim of a PC that isn't grounded. As soon as you plug the Hog into the PC, the Hog is grounded as long as the PC is already grounded.

 

The only warning to take from this thread is one that applies to any device you plug into a wall socket. Make sure things are properly grounded, and on the same ground!

Yeah sorry, that's what I meant - make sure you're properly grounded no matter what.

Maybe I shouldn't have referenced that with static frying but I have had a couple of experiences (non computer related) in the early days where the only thing that's probably saved my life is the safety switch.

[emenance]

Is the Hog Ul Certified? UL Standards ? http://www.ul.com/global/eng/pages/corporate/standards/

[Alex_rcpilot]

The OP mentions the Hog in this case, but the Hog had absolutely nothing to do with anything other than being the victim of a PC that isn't grounded. As soon as you plug the Hog into the PC, the Hog is grounded as long as the PC is already grounded.

 

Exactly. I was discussing the same thing with Dozer yesterday. It's not TM's responsibility to also take care of the grounding of the PSU. They'd assume that the computer was perfectly grounded, and devise the best solution for that.

 

While the fact is otherwise. Not 100% residents are equiped with perfectly grounded wall sockets. And people happen to live in places like that. Legals is another story. In such rooms, even with a qualified power cable and PSU, the PC's potential could still end up floating around.

 

Under those circumstances, it's kinda difficult to fix the grounding problem, then people would need work arounds and of course, precaution.

 

 

For other dudes, just to clarify some worries:

 

It doesn't take much energy to fry a component if it was a fuse already loaded with operating current. Designers add reasonalbe redundancy while picking a fuse for their devices. If the fuse was rated at 500mA and the device works on 420, an extra 100mA diverted through the case to the earth ground is enough to blow the fuse.

 

The potential difference is caused by electro-magnetic field emited by the fast switching components and absorbed by the case of the PSU. This creates a coupling of electric energy and makes the case equivalent to a 100V+ AC power source against human.

 

Fortunately because this weak coupling adds significant internal impedance to this exposed power source, it allows the voltage to drop below 36V when a grounded human touches the case. Although there's still current flowing through the human body, it's well within the safe current range of 30mA. In most ocassions it's below 5mA. But there's no doubt you gotta try your best to ground this sucker. Coz if the PSU happens to be an exception, there're still chances for someone to get electricuted.

 

The PSU posed no harm to my team mate, but it fried his hog, why? Because the human body has greater resistance than the steel support and metal screw. Although it's capable of carrying enough current to reduce the voltage on the case, it's not capable of generating the current overload to blow the fuse. So there's no need to worry too much about your computer if you understand the physics behind this whole thing.

 

Alright boys, fly safe, and fly happy.

[Wolf Rider]

 

We've just had a Warthog stick (right hand) resurrected from an earlier incident.

 

 

As he recalled later, he was mounting the unit to a steel support on the ground when this happend. The smoke was seen right after he tried tightening the first screw. With this piece of clue, the cause of the problem became apparent:

 

A. The PSU of his computer wasn't perfectly grounded, and there's potential difference between the power system of the PC and the earth;

 

B. Inside the HOTAS Warthog, the GND net could be connected directly to the metal case for better EMC performance or whatever;

 

 

The stick's metal surface IS the ground wire of your computer[1], it's an exposed part of a circuit. So prevent any contact from nearby conductors or electric static carriers.

 

 

could you describe the "earlier incident"?

 

as for the other from your post... if I have read correctly, is not possible - B and [1] isn't possible at the same time... it is either/ or.

If the casing was earthed and ground potential came into play, at most the weak part of the cable may fry.

Earth goes to Earth, goes to Earth... (unless there has been a connection made to an active in some manner... a manner like drilling, for instance) it is there for protection in case the active wire inside the casing works loose and energises the outer casing (if that casing itself is not earthed), which in that state, if a person should touch the energised casing and be standing/ leaning/ sitting on something which earths the person - results in a zap, or worse - electrocution... dependent of course on the size of the breaker and whether or not a residual current device/ earth leakage detector has been fitted. Good PSU's should shutdown at a earth leak being detected.

 

Having said that, there are problems associated with multiple earthing points over a largish area and differences in ground potential, such as temporary camp, (lots of powered tents containing electronics for instance in a military situations) or a theatre stage... hum through the speakers or band gear being the giveaway to an earthloop there, but could also just be a dirty transformer/ pcb on the same buzz bar.

Edited January 24, 2011 by Wolf Rider

[Alex_rcpilot]

could you describe the "earlier incident"?

 

The earlier incident was him blowing the fuse while mounting the screw.

 

as for the other from your post... if I have read correctly, is not possible

 

I guess you might got confused because some of my words, like "ground", or "Net".

 

Ground or symbolled as "GND" for short is a term used by electronic engineers to define a local reference point. If you talk about a ground and a 5V supply, it means the voltage is relative to this GND point. But the ground itself may have nothing to do with the earth.

 

Net as we call it actually is a member of a netlist which represents the connectivity of a circuit. It means an element which takes part in a circuit. In this case, the black wire in the USB cable is an object in a netlist, and it is connected to the GND net. Other objects which are on the same net include: all component pins connected to GND on every circuit board in the PC, the casing of PSU, the computer chassis, the 3rd pin in the PSU's power socket.

 

So B and [1] are possible to happen at the same time. Actually, it's because of B, that [1] can happen. These parts together make up a huge equipotential body which floats when not earth-grounded.

 

The weak coupling inside of the PSU plus the Y capacitor keeps charging this equipotential body to electrify it, and makes it worse than floating.

 

I think the black GND wire in the USB cable was also carrying leaked current when this type of shorting happend, but there was only one fuse on the PCB and the portion of leaking current through the fuse was enough to blow it. After the fuse was gone, the leakage continued through the black GND wire. :)

Edited January 24, 2011 by Alex_rcpilot

[Wolf Rider]

so the GND (black wire) is the "common"? and 0v at the chassis?

 

I can see that your "ground" is different to Earth... some might see ground and Earth as the same, hence the confusion.

 

RCD's/ ELCB's down here in Oz will trip and take out the power (mains) as soon as any voltage is detected on the EARTH line

Edited January 24, 2011 by Wolf Rider

[Alex_rcpilot]

so the GND (black wire) is the "common"? and 0v at the chassis?

 

I can see that your "ground" is different to Earth... some might see ground and Earth as the same, hence the confusion.

 

Yes, GND is the local 0V reference. And yes, I've occasionally made confusions. Given the massive terminology, it only takes a tiny negligent to totally mislead people on such topics. Perhaps we shall can the earth ground "PE".

 

RCD's/ ELCB's down here in Oz will trip and take out the power (mains) as soon as any voltage is detected on the EARTH line

 

A good power supply with Y capacitors inside would only leak less than 0.7mA to PE. Distributed capacitance between primary windings and secondary windings in the PSU's high frequency transformers might add a slight amount of current to it. This current is within the permitted range of an RCD. This current also prevents the voltage on the PE from rising, because as I said before, the leakage has very high impedance.

 

I'm a little confused at exactly how much extra current it took to blow that fuse. If it went over 30mA, then this computer would constantly trip an RCD if it was properly earth-grounded. Otherwise, the margin left on the fuse for overload redundancy was indeed very small. Maybe the fuse was rated under 500mA, and maybe as the crew made contact with the pedestal, the discharge of this energy created EMI which messed with the chip inside the hog and shorted its internal MOSFET's, and then, excessive current from 5V supply of the USB finished the job.

[Wolf Rider]

PE, it is then :)

 

what else was going on in the surrounding area? welding perhaps/ plugged in drill left on the ground?

[Succellus]

While the fact is otherwise. Not 100% residents are equiped with perfectly grounded wall sockets. And people happen to live in places like that. Legals is another story. In such rooms, even with a qualified power cable and PSU, the PC's potential could still end up floating around.

 

Wall plug with ground wire ? W'as that ?

Fact is, is you building is earlyer than the 80, ground wire in building is probably inexistent. And yes its hard seriously grounding anything that way.

But anyway its hard maintaining a good grouding when it exist cause of material degradation, earth property change , etc.

Hell, here ground plug only appeared in buidling in late 90, early 2k...

And go figure if they are really working or just for good looking.

 

Unles your certain your perfectly grounded, try to screw the hog on wood, or insulate the floor contact of the structure with rubber.

And if touching something where you re computer is plugged, you think you took some current, better review your PC PSU, line filtering, etc...

 

I alredy had some shocking experience with my cougar, but nothing happened, thanks the gods.

[spn]

Personally, I wouldn't invest that kind of money on a new product which has not had a proven track record for about a year or more, giving them time to get the hardware and firmware issues worked out. They're basically using the sim community to debug their issues at your expense. I am flying a $40.00 hotas and not having any issues. Knowing that I have a stable hotas then any issues that are happening with DCS A-10C Warthog are not being added to with other thirdparty products.

[Alex_rcpilot]

PE, it is then :)

 

what else was going on in the surrounding area? welding perhaps/ plugged in drill left on the ground?

 

Nope, not so much going on according to him. It's not a garrage like most of you guys may have.

 

BTW, I just tried floating the GND of my own rig, and then I measured 122V between the chassis and the PE hole. Guess it's enough to do some damage even not directly correlated.

[Alex_rcpilot]

Wall plug with ground wire ? W'as that ?

 

Not quite sure which type of cable he used, but he's definitely going to figure it out.

 

And yes, apply insulation wherever it is possible. Personally, I allways keep my products' cases insulated from internal GND if earth protection (PE) is not DIRECTLY accessible.

[Alex_rcpilot]

Personally, I wouldn't invest that kind of money on a new product which has not had a proven track record for about a year or more, giving them time to get the hardware and firmware issues worked out. They're basically using the sim community to debug their issues at your expense. I am flying a $40.00 hotas and not having any issues. Knowing that I have a stable hotas then any issues that are happening with DCS A-10C Warthog are not being added to with other thirdparty products.

 

I can't deny any part of that, but I can't resist the temptation from these new toys either. Currently I'm flying with my 7 year old X52. Still saving money to buy a hog.:music_whistling:

[Wolf Rider]

well, you've aroused my curiosity now...

we've been over the "static" thing on another thread and enquired about the habit of "heel dragging/ feet shuffling" over nylon carpet, but there wasn't (to be expected) response there, even though normal walking may cause some static build up, but not as much as dragging/ shuffling the feet, I would have thought

 

When you said "pedestal on the ground" I had assumed an earthen floor and a situation similar to single wire return power set up, or a dodgy welding rig doing the thing in close(ish) proximity or using mains power (look into 3rd harmonic and effects on the neutral), or similar.

 

yeah, if the throttle casing isn't earthed (PE), that is of a serious concern. (I couldn't find any compliance information in the TM manual, only the CE mark reference... which apparently can be certified "in house" these days(?))

Edited January 24, 2011 by Wolf Rider

[Alex_rcpilot]

When you said "pedestal on the ground" I had assumed an earthen floor and a situation similar to single wire return power set up, or a dodgy welding rig doing the thing in close(ish) proximity or using mains power (look into 3rd harmonic and effects on the neutral), or similar.

 

yeah, if the throttle casing isn't earthed (PE), that is of a serious concern. (I couldn't find any compliance information in the TM manual, only the CE mark reference... which apparently can be certified "in house" these days(?))

 

No, even if he had a welding machine, he would have known not to use it indoors so close to a computer.

 

Most houses here have simple paved floor and metal parts with large surface area sitting on the floor are easily grounded. They aren't as conductive as PE but should be enough to cause some problems.

[Wolf Rider]

I meant welding in/ around the general location, not the chap personally doing some welding.

[Druid_]

I take it all houses with 3 pin plug wall sockets (L,N & E) are safe? Although I have checked my plug to PSU to make sure the earth connection is good.

[Alex_rcpilot]

I meant welding in/ around the general location, not the chap personally doing some welding.

 

oh, well, I can't rule that out. Pity he hasn't got a multimeter, otherwise I could ask him to check a couple of times the AC current amplitude between his case and the metal pedestal. Can't always be someone around welding or using a motorized tool.

[Wolf Rider]

 

Pity he hasn't got a multimeter, otherwise I could ask him to check a couple of times the AC current amplitude between his case and the metal pedestal.

 

 

 

yeah, you could... plus any other objects in the immediate vicinity.

 

If you don't mind me asking, what is the mains supply set up?

[Alex_rcpilot]

I take it all houses with 3 pin plug wall sockets (L,N & E) are safe? Although I have checked my plug to PSU to make sure the earth connection is good.

 

Well true story here is unscrupulous real estate developers sometimes choose to ignore grounding reqirements, they falsify paperwork and bribe officials to cheat the acceptance procedure. When they get away with it, people will end up living in a building where the PE hole in their wall sockets are nothing more than a decoration.

 

And even if the building fully qualified all the standards required right after construction, the grounding could still fail over time due to numerous causes. Theift for example poses a major threat in rural areas where public utilities are poorly inspected and faulty equipment are often left alone. Corrosion and geo-environmental changes may also cause the protective grounding resistance to degradate (increase). Under such circumstances it's the property company's responsibility to replace the grounding conductor or lower the soil resistance by injecting some chemicals deep into the earth to improve grounding resistance (decrease).

[71st_Mastiff]

I think when I was in high-school. I was told to turn the power off and unplug the source before doing any kind of electrical work? I could be wrong though? :doh: