Need technical help - phantom power shut off

MTOU firewire

I have a new MTOU896mk3 - firewire. It has been working great when plugged into my desktop. Then I tried my laptop. This has happened 3 times. I am using a Lenovo and a TI chip set firewire PCMCIA card.
The unit seems to work when I am using WDM drivers, but if I change to ASIO the unit will play a file but it records only noise. Then when I try to change back to the WDM drivers, the phantom power disconnects. A dynamic mic can still be used. After the unit has set for a few hours, then phantom power is back on.
The MOTU tech says it has to be in the unit and they will replace it if I send it back to them (at My expense). I am wondering if there is some reason this is happening that is caused by the firewire situationo on the laptop. Something that would cause a curcuit breaker in the MTOU to shut down - the tech says no.
Any thoughts? I don’t want to keep returning units if it is the fault of the laptop setup.

Remind me again - what kind of laptop you’re using…

A Lenovo N100 - it’s an intel duo 2 T5500 running Windows XP.

If the 896 is wall-wart powered, and I believe it is… you should listen to the MOTU tech. If it’s FireWire buss powered, then the laptop may be the problem. There are two types of connectors for FireWire, the 6 pin and the 4 pin. The two “extra” pins on the 6 pin cables are for buss power. Most built-in laptop ports are 4 pin and WILL NOT supply adequate buss power. In cases like these, external units MUST be powered off a wall-wart OR an adapter that “feeds” the extra two pins on the 6 pin end of the cable.

Since I am pretty sure the 896 is wal-wart powered, it sounds like you have a dud.


That makes a certain amount of sense, the thing I don’t understand is why it works with the desktop. The MOTU is internal power, doesn’t use the firewire power. However, I am using a 6 pin cable/setup for both the laptop and the desktop (the laptop has a 6 pin PCMCIA firewire card plugged in. I just tried plugging it in to the four pin of the laptop and the meter when to scream. I then shut down and plugged into the desktop - works fine. Makes no sense to me.
I guess I will exchange it, but if they test it and it works, I’m not sure what they are going to do. I will run some more test - seems to me it was working with WDM drivers, could my ASIO drivers be so screwed that they would overload the phantom power?
I have a probelm with my Layla 20 and another desktop (yes, I am a computer junky, this one is my old layla that I retired to my office) anyhow, it will Not work with the ASIO drivers, but does work with WDM drivers. I think I will try some different software.
Any thoughts or suggestions would certainly be appreciated. I’m in over my head. I think you are right Diogenes, I just am reluctant to accept it. :heart-break:
Thanks for the help,

If it works perfectly on the desktop Bax… I dunno… Sounds fishy to me. Firewire is a great protocol, but it seems there are wonky chipset issues with a lot of manufacturers and their drivers. Can you check Device Manager on both your laptop and desktop to see if you can determine what Firewire chipsets they are using?


The firewire chipset is defiantly an issue.
That is why I am using the PCMCIA card with TI chips.
Seems that almost all the manufactures of firewire audio require TI chips and most laptops come with cheap “comparable” chips.
I think the issue may be with the chipset/driver for the PCMCIA
I was hoping that someone had defeated this issue, but the only safe option at this point is to return the unit and then see if the behavior repeats itself (then I get to buy an New Laptop - yeah!)
I called, they sold me the unit, and they will exchange at their expense.
Heck of better deal than MOTU is offering, they will accept the unit and send me a reconditioned if I pay for shipping to them.
Glad I bought the unit at Musiciansfriend.
Thanks D for the input - if you, or anyone else, has some idea to try, please let me know.

I think you made the prudent choice. :agree:

You’ve probably already read about my experience with my Presonus FireBox Firewire interface? I bought it to use with a laptop I had just bought, a CompaQ v2508m. I worked with Presonus tech support for two weeks trying to make the thing work. Upgraded drivers for both the laptop and FireBox, PCMCIA FW Adapter etc… blah, blah… Funny thing is, it worked perfectly with my other laptop and everybody else’s I could lay hands on that would let me try it. I told Presonus to skip it and I’d just use the FireBox with an alternate laptop.

My son has it now at school and it worked right off the bat with his new HP laptop and Vista. Go figure…

This same Compaq works like a champ with my little Tascam US-122L, so I’m all good I guess. Just don’t have the extra I/O and better audio specs of the Presonus.


I also had problems with the Presonus 24x24. Worked on it for 30 days with the tech people and everyone else that would try to help. then took it back. The drivers were just terrible. They kept saying they were coming out with new drivers, and they finally did, after the thing had been on the market over a year and a half. They had to kill off their Presonus forum because people were complaining so much. That unit did not work on any of my computers. This one works great on the desktop. I probably need an HP laptop (most have TI chips).