MDD won't turn on

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doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1335

Well, I am back from Afghanistan on R&R and upon my return home, I found that the wife reported our MDD will not turn on.

Behavior is as follows:
power button on case (or monitor) does not turn on Mac.

Attempted fixes:
1. Removed power cord, allowed to sit for several hours and reconnected. Attempted to push power button on case, lit for half a second and then nothing, no power on.
2. Removed power cord, disconnected all internal drives, removed all RAM, removed video card, hit CUDA button, let sit for an hour or so, reconnected power cord (only), same results. Put RAM back in and Video card.
3. Checked net, pulled PSU from case, opened it up, could not find "fuse" or any damaged components, looked brand new, albeit dusty, reinstalled PSU, started to pout, posted this issue here.

I am not really looking forward to paying for Genius Bar to tell me to buy a new Mac or PSU, especially if all I need is simple and achievable for the skilled with a soldering tool.

Questions:
What can I do to verify that it is the PSU? or have I beaten the horse to glue?
Is there a fuse that I missed which could save me more money than switching to Gieco?
Best/most cost effective solutions for replacing the PSU? (Looking for recommendations on vendors whom you have good results with, don't mind paying more for peace of mind.)

TIA
--DDTM

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

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Dr. Webster's picture
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Re: MDD won't turn on

I assume you're using an ADC monitor? If pressing the power button on the monitor doesn't power the Mac on, then you've effectively ruled out the button on the front of the Mac being the issue. Since it won't even power on or chime, that rules out bad RAM/hard drive/video card. You might be able to exonerate the power supply being the problem if you hook everything up then start checking for voltage where the PSU connects to the motherboard...at least a couple of rails should be putting out voltage for soft power.

Considering how inexpensive basic ATX power supplies can be, it might be worth a shot just to hack one up and see if that will get the Mac to power on.

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gsmcten's picture
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Re: MDD won't turn on

Doug Doug,

I just wanted to say Welcome Home and Merry Christmas.
When do you have to go back?

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Macinjosh's picture
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Re: MDD won't turn on

Dr. Webster wrote:

I assume you're using an ADC monitor? If pressing the power button on the monitor doesn't power the Mac on, then you've effectively ruled out the button on the front of the Mac being the issue. Since it won't even power on or chime, that rules out bad RAM/hard drive/video card. You might be able to exonerate the power supply being the problem if you hook everything up then start checking for voltage where the PSU connects to the motherboard...at least a couple of rails should be putting out voltage for soft power.

Considering how inexpensive basic ATX power supplies can be, it might be worth a shot just to hack one up and see if that will get the Mac to power on.

Im not as familiar with the MDD, but i think this is right on. Check for voltages, if theyre right then its not the PSU, and if they arent then it is.

Suspect LB or PSU. These have a battery right, is it flat? Does it act differently with it out or removed and reinstalled after several hours?

Didnt see reseating internal cabling or the CPU(s), might want to.

doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1335
Re: MDD won't turn on

Forgot to mention that I did put a new PRAM battery in as part of the process (call it option 3) and no change in outcome. I need to find my meter in the garage, but I begin my return journey tomorrow, so it will have to wait until this summer. I may pick up a stock replacement (could always trade it off later if it is the LB and not the PSU...)

on that note, if it is the LB, then I will just replace the whole machine. From what I have read already in researching this, I was pretty settled on the PSU, Dr.W pretty much finalized it right there.

Thanks!

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

eeun's picture
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Re: MDD won't turn on

If you haven't already, check out TheUltimateMacUser's thread here. In his case it was the CPU card.

Also check out here...a site now only available through the web archive. Good photos of the PSU (unfortunately not of the fuse location), and dangerously testing voltage with the PSU disassembled Shock. Mind you, that's something I'd probably very carefully do as well.

There is a fuse inside the MDD PSU, and it should be near the AC connector.

If it is the fuse, replacing it might only be a temporary fix, since something may have encouraged that fuse to do its job.

Finding your multi-meter is your best first move. See if you get any power at all over the connectors when you try to start the G4 (you should be able to check at the logic board connector by sticking your meter into the back of the PSU connector, or use a bent paper clip, etc. to do the same).

And, of course, welcome home.

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Hawaii Cruiser's picture
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Re: MDD won't turn on

I've been having strange power on problems with my MDD too. For months now, after shut down, it will not power on at all--no light in the button, nothing--unless I completely cut-off power to the PSU for a moment--I just turn off the power strip that the MDD is plugged into and turn it back on, and then the MDD will power up when the power button is pushed. The past week or so, I'm having problems getting it to power on at all. I can get it to finally power on after opening it up and hitting the cuda or pulling the battery and cutting power and then pushing the power button, but it's now gotten inconsistent. Sound like a dying PSU? But why the cut power for a moment deal?

TheUltimateMacUser's picture
Joined: Jan 28 2004
Posts: 613
Re: MDD won't turn on

Welcome home, Happy New Year, and thank you for your service.

Right... On to the MDD. With my situation (as mentioned above) replacing the CPU module did solve the issue. Be warned, if you remove the heatsink, you will need to replace the thermal compound. Unfortunately, due to the MDD's age, the Genius Bar people will not really be able to help you very much (they basically told me to go scratch). The fact that nothing happens when you press the power button leads me to suspect the power supply has bought it. If you've got a multimeter, plug everything in and (with the PSU plugged into the board) check for trickle power. Here is the pinout:

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doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1335
*UPDATE*

Given the need to get this machine back up and the lack of patience to do anything else, I will be taking this to the Apple Store for them to replace the PSU. Not the best solution, but what I must do. I will update again after it is up and running.

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

Hawaii Cruiser's picture
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Re: *UPDATE*

Personally, I'd just go onto Craigslist and buy something else--even a Quicksilver 867mhz--until you can afford something in the MacIntel range. There comes a point when old is just old. Anything previous to 867mhz, G3 or G4, is now lumped in the derelict category. Anything over 867mhz, G4 or G5, is now in the near-derelict category. MDD dual or Quicksilver, not a valuable difference these days, and you may just be chasing a rabbit down a dark hole trying to repair the MDD. A replacement PSU from Apple might be more expensive than just buying another MDD.

Dr. Webster's picture
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Re: *UPDATE*

Hawaii Cruiser wrote:

A replacement PSU from Apple might be more expensive than just buying another MDD.

I'd be willing to bet that a replacement PSU from the Apple Store would be very close to the cost of a used Intel Mac mini, which would run circles around anything G4.

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doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1335
Re: *UPDATE*

Well, the point is moot.

The Apple store does not carry that part any more for 'Macs that old', meaning I need to go third party or upgrade completely.

Budget is a huge factor. A replacement that would allow me to maximize on-hand hardware is essential, meaning the flat panel monitor and hopefully RAM. I could just put it aside and go for a laptop, but I still can only go a couple hundred when all is said and done.

Suggestions?

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

cwsmith's picture
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Re: MDD won't turn on

There are ways to adapt an ATX power supply for use in a MDD -- much more cost effective. Only downside is that you'll lose 28V to the ADC port (Apple Display Connector).

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doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1335
Re: MDD won't turn on

kinda want/need that though...

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1335
Re: *UPDATE*

can memory from a Power Mac G4 Desktop Dual 1.25GHz (M8573LL/A) go into a Power Mac G5 Desktop Dual 2.3Ghz (M9748LL/A)?

same for the AGP video card?

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--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

cwsmith's picture
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Re: *UPDATE*

doug-doug the mighty wrote:

can memory from a Power Mac G4 Desktop Dual 1.25GHz (M8573LL/A) go into a Power Mac G5 Desktop Dual 2.3Ghz (M9748LL/A)?

same for the AGP video card?

MDD dual 1.25GHz (M8573LL/A) uses PC-2100/2700 SDRAM, and *might* accept PC-3200 SDRAM.

PMG5 dual 2.3GHz (M9748LL/A) uses PC-3200 SDRAM. If you've got PC-3200 in the MDD (not likely), you're golden. If you've got 2100/2700, no go.

IDK about the vid card.

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Dozens of Macs; a handful of PCs; Apple ][e, ][c and ][gs; a few iPods; lots of parts
17 guitars, 2 baritone guitars, alto guitar, 6 bass guitars, bajo sexto, 3 ukuleles, mandolin, banjo, sitar
3/4 scale upright bass, 4pc drum kit, congas, travel congas, bongos, cajon, cabasa, 12 harmonicas
http://www.cwsmith.fmhttp://www.facebook.com/cwsmith2620