USB Hub Issues....

[inov8tr]

There is a lot of discussion about self powered vs. bus powered USB hubs. This seems to be some what of a problem in my installation and I was hoping someone could shed some light. Mike... You mentioned the Belkin hub at the bottom of the P5V page had a switch on it so you could select the power. USB hubs available now seem to be "smart" and do the thinking for you on which power they should use. GRRRRR!!!

My issues are two fold. First I had my MacMini running this evening with the 7" Lilliput and the USB hub was plugged into the MacMini. The external power cable for the USB hub was leading off to the P1900. I noticed a little red light on in the P1900. Since the P1900 is sitting on my desk, not plugged into anything but the USB hub via the P5V, this seemed bad. Unplugging the external power plug from the USB hub turned the light off in the P1900. So my USB hub is back-feeding the P1900, I'm sure the P1900 isn't going to be "belching flames" from this since it is pretty stout. But this is really frustrating!!!

I decided to take the USB hub apart and cut the incoming 5v line from the computer, that was a bad idea... Now only the power light for the hub comes on when you plug it into the wall, but rest of the status lights for the individual ports do not light up. (No flaming please, everyone has to learn their lesson at some point) So, the thing needs the 5v from the computer to operate properly. Well this is no good since I don't want to feed it 5v from the computer. I'll have to solder that lead back on tomorrow.

So the two questions from this long winded story are:

Does anyone know of a hub that truely only runs on external power or at least has a switch so I can do the thinking for the hub???

And, what are the ramificatons of the USB hub back feeding the P1900, once I actually install it in my car and power the P1900???

Any help is much appreciated....

-David

[mikeh]

David,

I'm not sure how in the world the LED on the P1900 can be lit by an external voltage applied to the P5V....??? This does not make sense to me. However, I don't believe it will damage the P5V or P1900.

It does sound like you may have a USB hub that takes power from EITHER the external input OR the bus, which ever is ON. The only experience I have is with the Belkin, which has a power selector switch.

[inov8tr]

Do you have the model number of the Belkin that you are using so that I can try and find one. The Belkin website doesn't have anything that looks like that so maybe they have stopped making them, or I'm looking the in the wrong place.

Thanks....

[mikeh]

The model number is F5U014. The hub is about 2 yrs old.

[inov8tr]

Mike,

Thanks for all your help. After a little further investigation of my USB Hub I came up with a solution. It is a little more unconventional, but it has worked really well. Don't know that it is recommended for everyone, but it has worked for my installation. I wanted to post it in case it will help anyone else out.

Here is a link to my CarMac project, specific with photos and a description of the fix.

http://inov8tr.blogs.com/scooby/2006...b_solutio.html

[mikeh]

Outstanding! Your work is very well done. Thanks for sharing with us. Good job on isolating your power issues in the USB hub. How about posting a link to your project in our "Your Projects" section? Also, I'm sure the Mac users at MP3Car would love to see your work.

Thanks again!

[Sabir]

Hi, This post is very informative, however I would like some specific information. If someone can help me then please send me a private message. Best Regards,

[s4per]

what other information do you need?