G4 Mac Mini USB port problem, strange one!

Discussion in 'Mac Basics and Help' started by Trail of Dead, May 17, 2009.

  1. Trail of Dead macrumors newbie

    May 17, 2009
    Ok, I am new to the forum and am new to Macs in general. My first Mac (a 350Mhz B&W G3) I bought 2 years ago and only used it a handful of times. I'm mostly a PC user.

    But anyhow here is the issue. I recently bought a G4 Mac Mini (1.25Ghz,512Mb,40Gb) off the bay knowing it had an issue with the USB ports. So I researched as much as possible about the problem prior to making the purchase. I'm a pretty tech savvy guy and figured it would be fun. But this has got me at my wits end. It has OS X Tiger on it and when you start it up it starts the "Welcome" in a billion languages movie, then it shows the the "Tiger getting started screen".

    After that it immediately pops up with a white screen of a keyboard that says one is not connected. My keyboard for this is an Apple wired aluminum one with white keys (just bought it about 4 months ago and can confirm it WORKS). My spare keyboard is an Apple B&W G3 keyboard and also can confirm it WORKS. I have two spare mice that I use for these kind of projects. One is a wireless Logitech "Cordless Optical Mouse for Notebooks" and the other is a Microsoft wired "notebook optical mouse 3000" model 1049.

    So, yes I switched them around on USB ports, nothing. I tried the PMU reset about 10 times, nothing. I replaced the CR2032 battery with a fresh one, nothing. So, I got curious....I have a USB LED light meant to clip on the screen of a notebook to illuminate the keyboard. I plugged it in and guess what it works! I also have a Thermaltake USB 80mm fan sitting on my desk as a fan to cool me off, it has a rheostat on it to adjust intensity. I plugged it in and tunred it all the way up and it worked just as good as it does on my HP desktop.

    So it seems it isn't a lack of power from these USB ports, it seems that maybe a controller meant to communicate with a mouse/keyboard just went deaf,dumb and blind. Am I right to assume that when you plug in a keyboard or mouse the PC/Mac sends a signal telling the peripheral to "turn on"? Cause it seems it isn't doing that. The LED light and fan don't need confirmation to turn on, they just need power....so they turn on. but my Keyboard and mouse don't do anything.

    I though it might have been Tiger (possibly?) so I removed the HDD and plugged in a wiped Hitachi 100Gb (2.5") and put in my Mac OS X 10.5 "Retail" disc in to see if it would change it's behavior. With the HDD blank it booted successfully into the Leopard disc and went right into the "choose main language" screen. Nothing, neither my keyboard or mouse worked at all. Anyone have any ideas?

    This is pretty strange right? I'm a PC guy so this is REALLY confusing! :confused::eek::confused:
  2. Trail of Dead thread starter macrumors newbie

    May 17, 2009
    I wanted to add that I HAVE searched very thoroughly this forum and everything else I could get my hands for a week straight regarding the issue my Mac Mini has. While I HAVE seen MANY threads where people have had issue similar to mine they are clearly NOT the same, or at least nobody has mentioned anything about their USB ports still powering other types of USB items but not detecting Keyboards/Mice.

    So, since I didn't see anyone reporting the same type of problem I posted a question hoping someone can help. Just figured I'd throw that out there before I get someone thinking "Oh look, another newbie with the same problem/question we see everyday. Looks like someone doesn't know how to use the search feature!"

    This leads me to another question....why does it seem like people have more problems with Macs breaking down (Speaking solely about the hardware here) than with PC's? I have never experienced as many problems with any PC (laptop or desktop) than I have with my Macs. I own a G3 Wallstreet, a G3 B&W, and now this G4 Mac Mini.

    It also seems as if not only are Macs REALLY expensive brand new compared to PC equivalents but parts are more expensive and harder to find. Don't get me wrong I totally dig OS X (when it's working) but man do these seem to have issues. :eek:
  3. RandomKamikaze macrumors 6502a


    Jan 8, 2009
    You will find on forums that you only read about negative experiences because people only post when they have got a problem. Considering the amount of Macs that are out there, and the amount of users on here, the amount that have problems, is really fairly low.

    I have a UMBP and have not had a problem with it since buying it about 6 months ago. I think it's great and would buy another Mac without giving it a second thought.

    With regards to your problem, it sounds like you have got a hardware fault, most likley to do with your Logic Board and the USB bus. Power is getting to the ports but the system isn't recognizing that you have got a device plugged in.

    The only thing I can suggest is to start replacing parts. Whether you buy these from eBay or you get them from Apple or a re-seller is up to you.

    And also I noticed in your first post that you brought this mini knowing that it had problems with the USB ports. As you brought this broken with the intention of having a bit of fun trying to repair it, you should've considered the possibility of hardware replacement. A broken USB port on a Mac or typical Windows computer is going to more than likely result in some sort of hardware replacement
  4. leavingwave macrumors newbie

    Apr 13, 2009
    So Cal
    if you're positively sure both your wired KBs work with other machines then the USB port on your Mini is bad. You need a new mobo.
  5. Trail of Dead thread starter macrumors newbie

    May 17, 2009
    When I bought it I was aware it had a "problem" with the USB ports...at least to the extent of the seller writing about it. Meaning, I didn't actually get to sit down with it ahead of time to determine if it really was a hardware fault. Not to sound naive but I personally have never had a USB hardware failure (with the exception of USB ports being physically broken from previous owners) in nearly 7 years straight of working on PC's.

    This is the first time I have ever experienced an actual failure in this area. However I did not rule it out as a possibility. Before I physically checked it out on the net and 85% (guesstimate) of the issues people have with USB port failure SEEM to be software related. A PC with a similar problem (to me) would be easier to diagnose and fix providing the PC had a PS/2 port. A simple tweeking of the BIOS or a total BIOS reflash after a standard CMOS reset and chances are you'd have the issue solved.

    If everything worked fine until Windows takes over then it obviously would require a reinstall of the OS. But with a Mac (at lease the Macs I own) this is all impossible. None of my Macs have a PS/2 port, so no chance of running a USB wired keyboard/mouse OR a wireless one. A USB bluetooth adapter won't work either! I was looking on the net for other ways to communicate with it but nothing seems to be feasible. I was thinking about buying a warranty for it and taking it to a local Apple Store but I don't know enough about the Apple Care warranty. It probably wouldn't apply to an old second hand G4 Mac Mini.

    Question? Are the CPU's in these things soldered on the board? Also, why are Mac Motherboards called "Logic Boards"? Why do "Logic Boards" always seem to need replaced? I go on the Bay everyday and see whats newly listed and WOW there are always TONS of iBooks, MacBooks, iMacs etc...etc...that say in the listing "needs new logic board" or "was told logic board is going bad" or something to that effect. I checked on there for a replacement "Logic Board" and the only ones listed for a Mac Mini are intel versions and they are around $300-400 USD!!! :eek:

    I'll probably just get another Mac Mini that is 100% A-OK and then just use this for an ITX project. Might be kinda cool to put a little ITX board in this case and make something cool out of it. We'll see! :rolleyes:
  6. msevild macrumors regular

    Oct 11, 2007
    When booting your machine try starting up the computer while holding down the command option p and r keys. Does the machine restart itself? Also try holding down the shift and s keys. Does the startup change when pressing this specific command? If startup is identical to when you are not pressing any keys down, then yes you have a system that needs a new logic board. As far as the terminology goes Apple just calls there boards logic boards. It is the motherboard of the machine, it has everything soldered or connected to it, for the mac mini it has the major components directly soldered to it.
  7. Trail of Dead thread starter macrumors newbie

    May 17, 2009
    I have tried resetting the PRAM but no joy. Question, everytime I restart it I have been pressing the caps lock key and it never lights up. I have been doing this to see if the keyboard is being recognized by the Mac. Am I wrong to assume it would light up? What I mean is could the keyboard actually be working even though the caps lock key doesn't light up both before OS X starts or after?

    It seems as if the "Agere" Southbridge/Northbridge chip has an issue. I assume it is the chip that controls the USB 2.0 functions all under "one roof" so to speak. If it does have an issue with the USB portion of it I wonder if there is a way to get that specific part up and running again via a reflash or something....kinda like an eeprom. Know what I mean?

    I'm saying everything else works fine, it boots up good, HDD runs great, the LED works fine, it plays the "chime" Combo drive works good, USB Ports have power etc...etc...it simply seems to me that somehow that portion of the "Agere" chip got corrupted. I wish there was a way to possibly burn a disc that can reflash it without any input from me. I suppose I am dreaming......:(

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