Welcome to the MacNN Forums.

danilon · Jun 28, 2007, 10:39 PM

I have a powermac G4 MDD that I just replaced the power supply:

There are times when I try to boot it, the button just lights up but doesn't boot.
After unplugging from the power stripper, then trying to reboot it, then it will turn on and work. But then At the middle of any session it will just die without apparent reason that I know. Could it be the power supply I put in is defective? I still have 2 months to return and have it replaced.

I tried resetting the PMU but it does the same thing.

Opinion Please!!!!

Thanks

OreoCookie · Jun 29, 2007, 01:32 AM

What do you mean by the `middle of any session'? Does the machine boot? Does it pass the Apple Hardware Test? Why have you replaced the power supply? Have you replaced it yourself?

This is just speculation at this point, but perhaps the motherboard or the RAM was damaged when your old PSU died. In any case, you need to provide more details. In particular, try to run the Apple Hardware Test (which is provided with each machine).

danilon · Jun 29, 2007, 09:35 AM

There are times when I boot the machine, it boots okay and I can do things.
And then, after a while, 30minutes or so the machine will die.
And I try to boot again, the button will just lit while pressing but it would boot.
So, I will let it cool down for a while and try it again, then it's okay again.

I replaced the power supply myself and I don't see anything wrong with that because the machine is running fine until I encounter such problem.

OreoCookie · Jun 29, 2007, 02:28 PM

Please run the Apple Hardware Test and report back what it says.

Big Mac · Jun 29, 2007, 04:40 PM

It definitely sounds like a power supply problem.

OreoCookie · Jun 29, 2007, 05:07 PM

Could also be a defective voltage module one the mobo that was damage by the first PSU or during the installation of the PSU.

danilon · Jun 29, 2007, 11:29 PM

Hi Guys,
So I spoke with the vendor and I have 90days warranty on the PS. I told him everything and he seem convinced that the PS might be the culprit.
He said, nothing is wrong witht the board, logic board, PSU or whatever. It is definitely th PS because it just dies all of a sudden.

I'll keep you posted...

thanks guys!

OreoCookie · Jun 30, 2007, 12:47 AM

PSU = power supply unit.

danilon · Jun 30, 2007, 01:43 PM

Oreocookie,

If any of those you mentioned were FAULTY or DAMAGED, the machine will not boot at all, right?
It's not that it will boot up, then you can surf (like what I'm doing right now), upload movies to Imovie to edit, print pictures from Iphoto THEN DIE OUT.

Comments anyone?

OreoCookie · 02:12 PM

No, that's not true. My last iBook had a faulty voltage regulator module and showed exactly the same symptoms you describe now: the computer would often work, but the intervals between failure were becoming shorter and shorter. While I think it's likely that the PSU (= power supply (unit)) is the culprit here, it doesn't mean that the rest of the system is fine. A faulty PSU can cause damage to other parts of your Mac.

Hence, please dig out your Apple Hardware Test and check the rest of the system! By the way, if the replacement PSU causes damage to the rest of your system, this is covered under warranty of the replacement PSU as well! It's in your own interest to exclude any other defects (possibly in addition to the PSU). Oh, and if you know that a component of your computer is failing, you shouldn't just continue to work on that machine. Do a backup immediately, find out what it is and have it fixed!

danilon · Jun 30, 2007, 07:42 PM

Oreocookie,

Here's what I found, I tried pulling the load piece by piece (DVD player, 2 extra HD's) and tried to reboot the G4 each time. I noticed when I close the door "IT DIES". I tried it several times and it really does kill the power. Oh boy! I'm sick and tired of this. Now, I tried running just the motherboard and harddrive with the OS in it and still under observation on this very moment.
Trying to transfer video fiiles to Imovie while typing this for you. I'll see what happens.
Where can I get that Apple Diagnostics? Oreocookie?
Thanks again.

reader50 · Jun 30, 2007, 08:44 PM

Have you tried a different power cord? It takes a standard office-type cord. A loose connection would explain all of your symptoms. ie - closing the side door jostles the power cord just a bit.

It's probably not that simple & cheap to fix. But it's worth checking, in case it is.

cgc · Jun 30, 2007, 09:16 PM

I suggest looking around the door assembly for any wiring that may be getting pinched by the door. A short would definitely shut your PSU down.

danilon · Jun 30, 2007, 10:29 PM

Reader50 and CDC,
that makes sense, applying my little knowledge in electronics, I think I isolated the problem. But still, it's under observation. I will leave it on overnight.
Amazingly it's not turning off for more than 5 hours now. Hmm!!

thanks guys for your support. I love it here!!!

Kenneth · Jun 30, 2007, 11:57 PM

Sometimes I had my DP 1.25 PowerMac G4 shuts down during the middle of the booting. I ended up pulling out all the USB cables (UPS, iPod Dock, iMod, printer). Reset the PRAM and fsck.

danilon · Jun 30, 2007, 11:57 PM

So Kenneth,
Did it fix the trouble when you did that? I did too and it seem to be fixed already. The machine did die anymore since 45 hours ago. I saved a lot of work already in Imovie, surf and answered your supports guys.

thanks again.

Zubir · Jul 1, 2007, 12:13 AM

May be something as simple as overheating. If if shuts down again, try running it with the door open slightly.

cgc · Jul 1, 2007, 11:09 AM

I thought leaving the door closed aided in cooling as Apple designed the airflow to go over certain components...

OreoCookie · Jul 1, 2007, 12:27 PM

cgc is right.
MDDs are dependent on a good airflow.

@danilon
What was the problem?

danilon · Jul 2, 2007, 12:39 AM

Thanks Guys!

danilon · Jul 2, 2007, 09:44 PM

I think so, MDD dies when heated so much. I should have known.
I left the door open for almost a day now and it's not shutting down.
Oh boy, should I buy an industrial fan to cool this down?
What's your recommendation guys?

angelmb · Jul 3, 2007, 01:57 AM

Maybe a PCI fan card would help.

My MDD (single 1,25 GHz) is not that hot, CPU -> 96F (36C) while three internal hard disks temp between 96F (36C) and 89F (32C) but makes too much noise.

danilon · Jul 3, 2007, 11:35 AM

Okay Guys,
Here's what I noticed:
I turned the machine "ON" with the door open AND a portable electric fan directed to the CPU. It was left on the whole day and night (24 hrs). The following morning I decided to close the door, then, counted 30min to 1hr, the machine died.

Hmmm!....experts....help...confused!!!!

angelmb · Jul 5, 2007, 07:01 AM

Originally Posted by danilon

AND a portable electric fan directed to the CPU. It was left on the whole day and night (24 hrs)

Once you closed the MDD's door… there was the fan still inside?, I guess it wasn't so that could mean an overheat issue as suggested by other members…

OreoCookie · Jul 5, 2007, 12:23 PM

… or opening the machine killed it, because other components didn't get enough ventilation. It really sounds as if the voltage regulator module could be the culprit here.

danilon · Jul 6, 2007, 05:49 PM

If the door is open, the machine will work TIRELESSLY. But if it's closed, expect 30min to 1 hour then the machine will die.

So Bizarre!