USB port not powering device

G

guitz

Member
I have an Akai MPD16 pad, that can run off USB power...I couldn't get it to power up in either USB ports on the PC...Akai support says it's very possible the ports aren't supplying enough juice to power it...I thought this sounded fishy , until I tried the box on an older pc with no peripherals attached and only 1 or 2 pci cards in it, and sure enough , the LEDs lit up when I powered it up...this leaves me with a dilemma....is it my power supply that's overworked, or possibly to many pci cards,etc plugged in , draining the power?...I have every pci slot filled with something...oddly, my USB powered M-Audio keyboard works fine ...the Akai tech guy says these MDP16 apparently need a certain amount of current or voltage....anyway, I wonder if I should invest in a new power supply or buy a 9 volt power adpator that I didn't come with it, and use the midi port instead....or maybe some tweaking in the bios can adjust the juice to the USB port...OR...maybe pull out all non-essential PCI cards , to lighten the load? hmmmm
 
altitude909 said:
Does it work when you unplug all your USB devices and just have the MPD plugged in?
Click to expand...


no, it doesn't...at least the LEDs aren't lighting when I push buttons....
 
I would try pulling out all of your other non-essential PCI cards to see if it is a load issue...

Are you using a USB port built into the motherboard? ... maybe this isn't providing enough power, maybe a new PCI > USB 2.0 card would provide more power?

I was about to order a Dell laptop the other day when I read in the small print the USB ports were unpowered, this put me right off
 
I'd get into your PC bios at startup and make sure the USB bus is enabled before I went pulling anything out of the computer.
 
Cazzbar said:
I would try pulling out all of your other non-essential PCI cards to see if it is a load issue...

Are you using a USB port built into the motherboard? ... maybe this isn't providing enough power, maybe a new PCI > USB 2.0 card would provide more power?

I was about to order a Dell laptop the other day when I read in the small print the USB ports were unpowered, this put me right off
Click to expand...


yes the port is built into the mobo...I'm thinking you may be right about pulling the non-essential cards, because it did power up on the much older pc (Abit BH-6!), with no peripherals....
 
LemonTree said:
I'd get into your PC bios at startup and make sure the USB bus is enabled before I went pulling anything out of the computer.
Click to expand...

well, it does power my MAudio keyboard right now....but like the Akai tech guy said, the Akai box may take more juice to operate.
 
guitz said:
well, it does power my MAudio keyboard right now....but like the Akai tech guy said, the Akai box may take more juice to operate.
Click to expand...

That's what I'm thinking. Some devices cannot be powered by the bus, and needs an ac adapter to run.
 
Mindset said:
That's what I'm thinking. Some devices cannot be powered by the bus, and needs an ac adapter to run.
Click to expand...

In this case, the device was designed to be bus-powered. It's more likely, IMHO, that the motherboard manufacturer cut corners and didn't provide enough current handling capacity on the USB ports. Solution: a $15 USB card. Unless your PSU is undersized, that should fix the problem, as the PCI spec requires ample power (5A per slot by my reading!) to handle a fair number(*) of USB ports per slot.

(*) 10 USB 2.0 connectors all operating at the maximum current limit....

Also, the maximum current allowed for a single USB device increased between USB 1.1 and 2.0, so if the ports on the motherboard are 1.1 ports, you should definitely get a USB card.
 
Cazzbar said:
I would try pulling out all of your other non-essential PCI cards to see if it is a load issue...

Are you using a USB port built into the motherboard? ... maybe this isn't providing enough power, maybe a new PCI > USB 2.0 card would provide more power?

I was about to order a Dell laptop the other day when I read in the small print the USB ports were unpowered, this put me right off
Click to expand...

There's no such thing as an unpowered USB port, or at least not that you can legitimately call USB. The USB spec requires a minimum of... I think 100 mA per port, and those ports are, AFAIK, only officially allowed in unpowered devices (unpowered hubs built into computer keyboards, mainly). Even those ports are powered. They're just "low power" USB ports.

Yeah, I'm sure you can point out some examples of some wildly noncompliant ports on handheld devices and/or cell phones---maybe even a couple that truly provide no power at all---but definitely not in laptops. I don't think you could get away with calling those ports USB, either. You'd probably have to call them "accessory ports" or something. I believe my Roomba has such a port internally. You get the idea.
 
a usb root hub (two ports) on a normal mainboard should have 500 mA per port available. The MPD draws no where near that (100 mA) so there is something else going on. My MPD works fine via USB although I just run it via midi since the akai driver is pretty bad
 
try a different usb cable :D

ha noone said it yet i figured they would
make sure its not a usb 2.0 device youre trying to use with a usb 1 port.
 
dgatwood said:
There's no such thing as an unpowered USB port, or at least not that you can legitimately call USB. The USB spec requires a minimum of... I think 100 mA per port, and those ports are, AFAIK, only officially allowed in unpowered devices (unpowered hubs built into computer keyboards, mainly). Even those ports are powered. They're just "low power" USB ports.
Click to expand...

Yep, you can't have a non-powered USB port, yet that's exactly how Dell are advertising their USB ports on their Inspiron 6400 laptops!

http://www1.euro.dell.com/content/products/features.aspx/notebooks_better?c=uk&cs=ukdhs1&l=en&s=dhs

(product details/tech spec tab)


I / O Ports

4x USB 2.0 4-pin connectors (non-powered); 2 at rear, 2 on right-hand side of notebook system
IEEE 1394 (Firewire): 4-pin serial connector, non-powered


so it's a complete oxymoron, notice they've also used "non-powered" for their firewire port, and this really does mean no power as it's only 4 pin

Sorry to hijack the thread, but I think we've all learnt a little more about USB power, haven't we :o
 
woes continue....

well, things are not any better after about 12 hrs or so of 'troubleshooting' lol...after believing I had the power issue sorted out, a much worse software catastrophe occured! , then more original troubles.....Here's the details , if yer interested :D....

so after seeing the mpd-16 light up on the old pc, I decided to pull out all non-essential pci cards AND reinstall windows on my main recording pc...after that, .....success! The lights lit up when I pushed buttons, I'm thinking sweet, now just a matter of installing the mdp-16 software AND the USB drivers...well, the small utility software that allows you set the pad sensitiviyt,etc installed just fine, and the little windows balloon popped up, stating that it was recognizing the Akai unit, and I proceeded to install the USB drivers....almost all they way thru the progress bar of files being copied.....BAM!...windows spontaneously reboots!....No idea at first what caused this, then upon rebooting , I discover my 2 audio cards - Audigy 2 and Echo Layla 3G , AND my cd/dvd drive are all missing!...Drive is completely gone from 'my computer'....audio tab is greyed out in control panel....At first I wasn't aware that this was a result of trying to install the USB driver for the MPD-16, so I reinstalled windows yet again, did the same thing all over again and exact same results at the exact same point...cd/dvd and audio cards all gone from windows during the MPD-16 driver install...This time, I used system restore to get me back to the pre-mess with the drivers and called Akai tech support again...he tells me to use the drivers off the akai webpage (which I had done)...so then he thinks it may be an IRQ conflict, which sounded reasonable to me...and he said that was about as far as he could 'troubleshoot' the problem, and also suggested trying a 2 or 4 port PCI USB card and disabling the on-board USB ports.....Not knowing how to manually rearrange IRQ's (and not really wanting to tinker in the BIOS) , I bought the PCI to USB card today, that he suggested....got that installed, and wouldn't you know it, back to the original problem, the MPD-16 doesn't light up now when pushing buttons!...furthermore, windows regonized it this time as an 'unkown device' and said there is a problem with it, and trying to manually install the drivers didn't work either, I dont' REALLY think the problem is the unit, because I also managed to power it externally with a 9volt power adaptor and using only the midi cable with no USB driver installed...this works in SONAR, ...BUT, I can't seem to be able to set the pad sensitivity without being able to use the utility applet, which doesn't recognize the device without having the USB driver installed! DOH!....Next move is take this pci to USB card back, and possibly get a beefier power supply (mine is 350 watt)...
 
Welcome to the wide world of wack Akai software drivers. I have been bitching to them about the terrible quality for years now (on my second MPD). They finally release updated drivers last year but it made no difference. The MPD will crash just about any system (it did this on my last 3 computers) if left plugged in via USB and not being used.

I only plug mine in via USB if I need to program it, otherwise, I run it via midi. The latency is lower this way and it does not bring down the system
 
altitude909 said:
Welcome to the wide world of wack Akai software drivers. I have been bitching to them about the terrible quality for years now (on my second MPD). They finally release updated drivers last year but it made no difference. The MPD will crash just about any system (it did this on my last 3 computers) if left plugged in via USB and not being used.

I only plug mine in via USB if I need to program it, otherwise, I run it via midi. The latency is lower this way and it does not bring down the system
Click to expand...


are you able to adjust the pad sensitivity ok without the USB utility?...I've fumbled with the '16 levels' button, but haven't gotten the results I want, but it may be the simplistic drum soundfont samples I was using....
 
guitz said:
Not knowing how to manually rearrange IRQ's (and not really wanting to tinker in the BIOS) , I bought the PCI to USB card today, that he suggested....got that installed, and wouldn't you know it, back to the original problem, the MPD-16 doesn't light up now when pushing buttons!
Click to expand...

Partially short-circuited USB port on the Akai, maybe?
 
guitz said:
are you able to adjust the pad sensitivity ok without the USB utility?...I've fumbled with the '16 levels' button, but haven't gotten the results I want, but it may be the simplistic drum soundfont samples I was using....
Click to expand...

There are only 3 settings possible and you dont need the usb to change them. Full velocity sensitivity, 16 levels via the button, and full level (meaning 127). How is velocity mapped in your sampler?
 
altitude909 said:
There are only 3 settings possible and you dont need the usb to change them. Full velocity sensitivity, 16 levels via the button, and full level (meaning 127). How is velocity mapped in your sampler?
Click to expand...

well that's good to know then...I wasn't using a software sampler, just loading the soundfonts inside SONAR,...I'm also thinking about purchasing EZ Drummer, and I wonder if the velocities or input sensitivity can or has to be mapped as you say for that?...
 
Well for the velocity to work, you need a device that responds to velocity in some manner. I usually just map velocity to the sample level on my sampler
 
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