[G4] Re: MDD no start, grey screen, no bong

[Technophobic_Tom at comcast.net]

On Thu, 26 Apr 2007 at 2:11 PM, I wrote:

>On Wed, 25 Apr 2007 22:08:06 +0000, Nate wrote:
>
>>Unplug the machine, open it up, take the battery out.  Press the 
>>PMU button (I use the eraser part of a standard wooden lead pencil) 
>>and hold it down for a second or so--you may hear a very faint 
>>click.  Wait about 15 minutes, then put the battery back in (check 
>>the voltage again first).  Close it up, plug it in, then try again.
>
>As I stated, I've done that..."I've tried every possible combination 
>of PMU and battery antics that I've seen on the forums and that I 
>can matrix." I unpluged the 120 AC, took out the battery, let it set 
>over night, pressed the PMU, came back hours latter, replaced a new 
>battery...nada. I've also done the same with all external cables 
>remove including the mouse and keyboard...nada. I've done that with 
>the video card removed as well...nada.

I think we need to clarify something here before someone gets lead 
astray by the wrong idea. The above procedure is NOT a 
recommendation. Nate was just proposing it as a last ditch 
alternative...I think. The Apple advised method of resetting the PMU 
chip is to disconnect the computer power cord, press the PMU one 
time, wait ten seconds, plug the power cord in, and start the 
computer.

The battery MUST be in its holder when the PMU button is pressed so 
that the PMU circuitry has power to reset itself.

If the battery is suspect, it should be replaced after the power plug 
is disconnected. Then, after waiting 10 seconds for the circuits to 
stabilize, the PMU may be pressed, the power plug may be reconnected, 
and the computer may be powered up.