G4 is DEAD! No boot tone, no LED, no activity!

[Corey Shay]

Pro Tools crashed on me today. Nothing new really. Then after I tried to quit DAE it locked up. This happens too... Hit the reset button, and got no boot tone from the G4. Upon closer inspection, the power button light is off. No Display activity whatsoever. I searched around the web and found some info on a power mangagement reset button. Hit that, but didn't help.

It just sits there. The only sign of life is a spinning power supply fan. It's basically brain dead. I noticed a bright red LED by the DIMM slots is lit when I power it on but I can't remember if it's supposed to be on or not. I've tried taking out all my cards and still nothing.

It's a G4 DP-450. And I got clients wanting CD's, but I can't work at all anymore.

[Milamber]

Corey,

It could be that you have encountered the power switch problem with the G4 Gigabit machines:

http://www.zdnet.com/zdnn/stories/news/0,4586,2653569,00.html

If so, the fix is to take your Mac to an authorized reseller and they will swap out the power switch assembly and possibly the logic board. Apparently the logic board fries the power switch.

When this happened to my G4/400, I was able to get it up and running by doing the following (while waiting for replacements parts to arrive at the dealer):

1. Unplug the power cable.
2. Wait 5 seconds.
3. Plug in the power cable.
4. Open up the computer.
5. Unplug the ribbon cable that connects the power switch to the motherboard. It is located in the front left of the motherboard, near the modem.
6. Wait 5 seconds.
7. Plug the cable back into the motherboard and the machine should boot.

Another fix is to use an older Mac keyboard that has a power button on it.

Good luck!

Milamber

[Corey Shay]

Thanks for the quick response Milamber, but I don't think I have the problem you described. The power switch works fine, as it turns on the power supply when pressed, and illiminates briefly before going out. Then of course I don't hear the chime sound, and no display. I fear the motherboard is fried.

[A.Confusione]

There is a reset button on the motherboard.
Press it and see what happens.
The exact same thing happpened to me a few months ago, and this worked.

[Ben Jenssen]

Similar thing has happened to me too a couple of times. My fix is simple: plug out power cable - wait a couple of secs - plug in - power up. Doesn’t feel right though.
My feeling is that it has something to do with total power consuption... just guessing, it seems it doesnt happen when i let disks on my SCSI-card spin up before I turn on Mac.

[Juergen]

Corey, it might be possible that you and I have (or had) the same prolem. I had my G4 (400 SP) crash on me a few times one day (installing and trying to run the Rebirth Demo), since it was late at night, I called it quits. The next day, I heard the drives spinnin' and the fan turnin', but nothing ever showed up on screen, nor did I hear the startup chimes.

A bunch of nice people helped me out in trying to troubleshoot it very, very specifically, and step by step, here is a copy of the thread. I hope it can be of some help.

http://duc.digidesign.com/ubb/Forum16/HTML/004991.html

To make it short, my problem ended up being a faulty logic board (motherboard) problem, which had to be replaced (for free, of course). I am in Southamerica, but I bought the G4 in Nashville, so I sent it up to the US for warranty reasons. It is on its way back. It might or might not be the same problem.

If your Mac's symptoms are the same, it might be good to try the things the people on my old thread suggested. At least that way you'll be able to find out if it is the motherboard or not.

Good luck!

Juergen

[snoopy]

I had this same problem when I put mine in a marathon rack. I learned that the motherboard is very suceptable to bends and even the slightest will cause the video baord not to seed properly (to slight for the naked eye) and adjusting the motherboard mounting screws until it came on was the fix.

Perhaps removing all cards, hitting the reset switch on the motherboard itself and reseating the video card might help. Also, remove any excess ram to ensure you don't have a bad stick.

Just some suggestions.

[The Recordist]

Resetting the PMU Chip Procedure

1. Disconnect the power cord and check the battery in the battery holder
(BT1). The battery should read 3.3 V to 3.7 V. If the battery is bad, replace
the battery, wait ten seconds, and then reset the PMU (refer to the next
step). If the battery is good, go to the next step.
2. Press the PMU reset switch (S1) once on the logic board. Do not press
the PMU reset switch a second time because it could stop the PMU chip
from responding.
3. Wait ten seconds before connecting the power cord and turning the
computer on. If the computer turns on, go to the next step. If the computer
does not turn on, there is something else wrong with the computer.
4. Run MacTest Pro and return the computer to the customer.

Note : This entire procedure resets the computer's PRAM. Be sure to reset thecomputer's time, date, and other system parameter settings.

[This message has been edited by The Recordist (edited January 26, 2001).]

[JC925602]

The red led is there to indicate that there is power on the motherboard.

Your computer may be in deep sleep mode (i.e. coma), that is:

• nothing in memory but the mac is stuck in sleep mode

...so there is no software to wake up the mac. That's why you don't ear the boot tone, the computer don't even try to boot.

The Recordist info about removing the battery is very important.

JC