Does anyone know what this connector is for on my USB card?

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Kookoo

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#79613 19-Mar-2011 23:37

I got my replacement motherboard today (thanks ASROCK), but before I hook it up I am keen to make sure I don't repeat the same mistake that might've fried my previous one. Here is a photo of a usb card I am using - it has 4 external USB ports, one internal, and 2 USB headers. But it also has what appears to be a power connector, labelled DCN-2.
Does anyone know whether it is power in or power out, and what I am supposed to hook up to it, because not a single connector on my modular PSU is a perfect fit for this port?

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#449977 20-Mar-2011 06:00

Looks like a standard floppy drive power connector (which is relatively common to power addon cards that need extra power)

Does it not have a manual?

*edit* given the screenprint directly under it of a molex shaped connector but with no connector, I'd safe to say it's a 4 pin berg FDD power connector.

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mckenndk

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#449994 20-Mar-2011 10:08

Defently a power boster as it's just a usb hub it will not be able to suppy enough power to all the usb ports if you have muitply things that get their power from the usb hub connected. e.g external hard drive, mouse etc.

You can see that there is the outline for a standard power plug on the card as well just has not been soldered on.

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gzt

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#450012 20-Mar-2011 11:54

I don't know the answer to your question, but the maximum specified draw for USB 2.0 is 2.5W (per port, from a hub).

On the maximum power available from the PCI bus -> Wikipedia:

"At least one of PRSNT1# and PRSNT2# must be grounded by the card. The combination chosen indicates the total power requirements of the card (25 W, 15 W, or 7.5 W)"

5 ports x 2.5W = 12.5W. Well within the ability of PCI to supply.

Having said that, I have no idea about the design of the card, it may be designed with external power in mind. Does the card operate without it?

What exactly was the mistake which fried your previous motherboard, if it is not too embarrassing ; )

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Niel

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#450026 20-Mar-2011 12:37

Many low cost USB devices will draw as much power as the port will deliver, often sensing the voltage so see when it starts dropping out. It is not uncommon for a device to draw up to 1A for charging, because 5W (= 5V x 1A) power adapters is a common size.

A motherboard will supply maybe 4A or 5A before limiting, because they use 1 protection device for all the ports (saving cost).

Contact resistance of the PCI connector will limit how much power you can deliver.

Only a few years ago the USB charging standard was released which allows up to 1.8A for charging, before manufacturers did whatever is needed to overcome the limitations of the USB standard. If you want the adapter to be a charging port then you should connect the extra power connector.

As an example, the iPad needs a 1.1A port for charging properly and is supplied with a 10W (2A) power adapter.

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Kookoo

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#450044 20-Mar-2011 14:22

Thanks all. I've tried the fdd connector before, but the fit was a bit too tight - it actually bent the white plastic on the connector on the hub almost to the point of breaking.
The way I think I've fried the mobo the last time was like this. I had a front panel card reader with usb ports connected to the usb headers on the motherboard, and the front usb ports of the case connected to the headers on this hub. All four rear panel mobo usb ports were already used for other devices including an mp3 player and a logitech wireless keyboard/mouse combo. I then connected an asus bluetooth adaptor to a hub external port, a tp-link wifi adaptor to the hub's external port, an adata 8gb flash drive and a samsung camera to the front case ports, and a sierra 3g modem to a card reader usb port. The hub was not connected to power.
Outcome: The mobo headers died completely, the mobo rear ports and the hub became permanently usb 1.1.

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gzt

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#450060 20-Mar-2011 16:17

If you are concerned this may occur again, a good quality external / ac adaptor powered hub is the way to go. This will remove all load from the MB/PSU. The worst you can do in that case is destroy the external hub. Good protection in case one of your usb devices is faulty in a suck-lots-of-power sort of a way.

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#450075 20-Mar-2011 17:40

I may be wrong, but at present I think there are very few motherboards (if any) which actually meet the USB Charging Specification. Perhaps Gigabyte, with their high power usb feature, but it is not clear if they actually build to the specification.

I also have doubts about many MB's implementing over-current protection, let alone over-current limitation - I think they just rely on the power supply to handle it or not.

Asus boards (some) do implement an overcurrent protection feature at the bios level tho.

I am not knowledgeable about these things, but that is the way it looks to me.

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Kookoo

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#450090 20-Mar-2011 19:09

Lias: Looks like a standard floppy drive power connector (which is relatively common to power addon cards that need extra power)

Does it not have a manual?

*edit* given the screenprint directly under it of a molex shaped connector but with no connector, I'd safe to say it's a 4 pin berg FDD power connector.

Doesn't have a manual - I bought it second hand because I couldn't find a brand new one with USB headers. All the new ones seem to have only USB ports.
It's definitely not a berg FDD connector - the distance between the pins is the same, but the berg connector is wider, and both the berg and the hub connector have protruding parts in the plastic same distance from the edge. On the hub connector it's a protruding line going across the connector, and on the berg it's a narrow slide-in in the middle, but they both bulge at the same distance from the edge, so you can't really connect one to another. Any ideas what else it could be?

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gzt

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#450102 20-Mar-2011 19:43

how about a good contrast close up of that connector, and the reverse side of the board near the connector.

Kookoo

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#450115 20-Mar-2011 20:16

gzt: how about a good contrast close up of that connector, and the reverse side of the board near the connector.

Hope this is good enough:
Front

Back

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gzt

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#450144 20-Mar-2011 21:11

I hate to ask this, but are you (correctly) inserting the plug - with the wide part facing down towards the board?

Just had a look at some Belkin cards online, and they do specify a floppy power connector.

If you can be reasonably sure about the pinout, and it still doesn't fit, then trimming some plastic to make things go together might be in order.

I would still go for an externally powered hub tho. Niel pointed out that many manufacturers have been essentially non-compliant for some time - and for many manufacturers, I don't think that will change anytime soon.

If you really want to get technical, you could hack a usb extension and insert a multimeter to determine the drain (charge from flat, normal operation, etc) from each of your usb devices.

Niel

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#450152 20-Mar-2011 21:23

Next to the un-fitted Molex connecter it says DCIN-1. Next to the fitted 4 pin connector it says DCIN-2. It is a DC input connector.

Motherboards usually have 1 fuse for all ports. Either a blow-once fuse, or a self resetting fuse (polyfuse) but less likely. A well designed motherboard will have a MOSFET and current sensing. A polyfuse is cheaper, but adds significant resistance and thus voltage drop. Very often they use a single use fuse.

Your expansion card has 1 MOSFET for isolating the PCI power supply from the external power supply. I can not see any fuse or current limiting elements. If you draw (far) too much power you will probably blow a resistor (0 Ohm link) and loose that port.

There are a few manufacturers that implement the dedicated charging port, which often does not support USB communication. For example I've seen a Samsung netbook with one. A device detects it as a charging port because the data lines will be shorted together, and then can draw up to 1.8A without negotiating for it. I don't think motherboard manufacturers do that. A number of mobile phone manufacturers adopted the standard and now use a common charger (finally) with a micro USB connector.

Last year I've researched this subject in order to develop a product which is just about to go into production. You will be surprised how few manufacturers comply with the USB spec. In order to get approval part of it is you have to travel to the US with your product and demonstrate your product behaves on their set of devices. Has to be in the US, nowhere else in the world. All other standards you send your product to a local accredited test lab, not so with USB.

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Kookoo

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#450172 20-Mar-2011 21:45

gzt: I hate to ask this, but are you (correctly) inserting the plug - with the wide part facing down towards the board?

That was a question worth asking, but I wish I wasn't - that would've made things much simpler. The berg connector has a protruding rail of sorts on the top that prevents it from being inserted in any other way but wide side down. It is located between the first and the second pins from left.

gzt:

Just had a look at some Belkin cards online, and they do specify a floppy power connector.

Typically, the jack for a berg FDD connector would have a hole in it to accomodate for the tongue-like catch on the berg. You can see it here between the second and the third pin, towards the leading edge of the connector.

Here is a front view diagram - I have never seen a different berg minimolex to this one:

gzt:

If you can be reasonably sure about the pinout, and it still doesn't fit, then trimming some plastic to make things go together might be in order.

My OCZ PSU cabling has the pins labled (which is awesome), and if I am right in assuming that on this hub the ground is designated by having rectangular soldering (I think it is soldering anyway) on the back of the plate, then gound seems to match, and i'd expect everything else to match also.

gzt:

I would still go for an externally powered hub tho. Niel pointed out that many manufacturers have been essentially non-compliant for some time - and for many manufacturers, I don't think that will change anytime soon.

If you really want to get technical, you could hack a usb extension and insert a multimeter to determine the drain (charge from flat, normal operation, etc) from each of your usb devices.

Not very keen on having another appliance on the desk, but if I have no choice - I'll go that way. ASRock implemented some sort of hack for their motherboards on the OS level that allows increased voltage to USB ports. I haven't installed it prior to frying my motherboard, but now I wish I have.

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gzt

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#450188 20-Mar-2011 22:12

Kookoo: [...] The mobo headers died completely, the mobo rear ports and the hub became permanently usb 1.1.

Before you do anything too radical, you might want to see if that pci card is providing USB 2.0 in the new configuration.

Kookoo: Not very keen on having another appliance on the desk, but if I have no choice - I'll go that way.

It sounds like a possibility you have a faulty usb device, and it will be a bummer if it takes out a second MB.

Here is a front view diagram - I have never seen a different berg minimolex to this one:

I don't have a floppy drive I can easily get to this evening, but my recollection is the older connectors did not have a locator, and it was possible and easy to connect them the wrong way around (therefore the connector was slightly different).

Niel

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#450197 20-Mar-2011 22:44

The square solder pad has nothing to do with GND. It is the pin-1 identifier. On some connectors that happens to be GND, but a square pad does not mean GND.

They could have fitted the wrong connector, which is why it is not documented. Replacing the connector with the correct one will cost a lot more than the profit of selling it undocumented. Or it could have been designed for something like a Dell PC which has custom connectors, but they manufactured extras and sell them unbranded and without the power loom. Or it is just a bad copy.

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