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PowerMac G4 won't start

D

Dcentuori

macrumors newbie
Original poster
Nov 19, 2011
25
0
Cleveland, OH
I've kept an old G4/466 under my desk at work so I can access legacy files from time to time. Just the other day I tried to turn it on and it wouldn't start. It worked as recently as September. I tried the reset button on the front and the CUDA button inside. (Couldn't do the keyboard stuff since I'm using a PC keyboard) Still nothing. I tested the internal battery and it is low--2.6 volts--but not dead. Could that be it?

I'm pretty sure it's the Digital Audio G4: model # M5183, EMC 1862.

Thanks,
Dante
 
Dcentuori said:
I've kept an old G4/466 under my desk at work so I can access legacy files from time to time. Just the other day I tried to turn it on and it wouldn't start. It worked as recently as September. I tried the reset button on the front and the CUDA button inside. (Couldn't do the keyboard stuff since I'm using a PC keyboard) Still nothing. I tested the internal battery and it is low--2.6 volts--but not dead. Could that be it?

I'm pretty sure it's the Digital Audio G4: model # M5183, EMC 1862.

Thanks,
Dante
Click to expand...


That battery would need to be replaced. The G4s are VERY finicky when it comes to booting up. If you need any more parts for it, let me know, mine has a dead motherboard.

I put one of these in my iMac G3, it will work for yours too: http://www.amazon.com/Saft-LS14250-...9959216&sr=1-2&keywords=half+double+a+battery
 
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Ah, great, that's what I needed to know! I'll get two so I can also replace the one in my G3 Beige Desktop I have at home, before that craps out too.

Thanks,

Dante
 
So, it can run without the battery? I thought that powered the internal clock or something like that.

I'll give that a try; shouldn't take too long with that great user-accessible G4 design!

Dante
 
What happens when you try to power it up?

Does the power button light up? Do you get a startup chime or any other sound from the speaker? Do the fans(either the PSU fan or the main case fan) spin or at least "twitch"?
 
First, I tried starting w/o the battery, and nothing.

Second, in answer to bunnspecial's questions, absolutely nothing happens when I try to start it. No twitch, light, fan, sound--nothing. With apologies to Charles Dickens, the Old G4 is as dead as a door-nail.

Does that make a difference?

Thanks,
Dante
 
Dcentuori said:
First, I tried starting w/o the battery, and nothing.

Second, in answer to bunnspecial's questions, absolutely nothing happens when I try to start it. No twitch, light, fan, sound--nothing. With apologies to Charles Dickens, the Old G4 is as dead as a door-nail.

Does that make a difference?

Thanks,
Dante
Click to expand...


Interesting, sounds as if the PSU or the power button isn't working.

powermac_pinout.png


I think if you jump the PWROK pin to COM it will turn on, this will test the PSU, it should spin fans, drives, etc.

EDIT: or (if applicable) PSU_ON to COM.
 
128keaton said:
That battery would need to be replaced. The G4s are VERY finicky when it comes to booting up. If you need any more parts for it, let me know, mine has a dead motherboard.

I put one of these in my iMac G3, it will work for yours too: http://www.amazon.com/Saft-LS14250-...9959216&sr=1-2&keywords=half+double+a+battery
Click to expand...

I hate to interfere here but whats with all the lies? This site says free shipping and when i get to the end to ship 2 of these it says $4.50 shipping. Im in Canada. but still what the heck?!
 
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As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
Dcentuori said:
Ah, great, that's what I needed to know! I'll get two so I can also replace the one in my G3 Beige Desktop I have at home, before that craps out too.

Thanks,

Dante
Click to expand...

You have a 466Mhz PowerMac G4 DA, and a Beige G3 desktop?! I have those same machines too!


It sounds like a bad PSU. PSUs can fail over time, even when not in use, especially if you are in a hot location (like in Nevada or Arizona). I had a beige G3 desktop and the PSU leaked LOTS of capacitors, just by sitting in a closet in a desert for a few years or so.
Look inside the PSU with a flashlight. Look for leaked capacitors. If you find some then you know the PSU is bad.
 
I'm off for a few days, so won't be able to check the G4 just yet. But I did pop out the battery and took it home. Tested it again and it is 3.6volts after all. (I got the 2.6 reading by testing it while still in the board--didn't remove it) So it's not the battery and looking more like the PSU--I'll know on Friday!

Since I only have the G4 to open files I have on disc or thumbdrive, I'm not married to it and can find other means if the repair is too involved. I don't think we have other G4s lying around at work, but I'll check and see if I can swap out a PSU.

As for my old G3, that one is our own and got it back in 1998, about 2 months before those sleek iMacs came out! I still occasionally need to go in there to open an old file. One day I may need to do a wholesale conversion, instead of case-by-case, since I know sooner or later it will get next to impossible to read the files. But that is for another post! Right know, I'm enjoying a bit of the "good old days" when you can open the case and get your hands dirty. Kind of like working on my car....

Thanks,
Dante
 
Now I wish I went into work today--all these things I need to try now!

Back to the pinout jumper suggestion 128k posted.... Are you saying that I should run some jumper between the PWROK pin and any COM pin, then close it up and turn it on? Or is this a test that needs to be run while it is live? Like as soon as I jump the pin, it will start (if that component is still good). Just want to be sure about technique. (Of course, it may make more sense if the machine was in front of me....I should have brought it home....)

Thanks,
Dante
 
Dcentuori said:
Now I wish I went into work today--all these things I need to try now!

Back to the pinout jumper suggestion 128k posted.... Are you saying that I should run some jumper between the PWROK pin and any COM pin, then close it up and turn it on? Or is this a test that needs to be run while it is live? Like as soon as I jump the pin, it will start (if that component is still good). Just want to be sure about technique. (Of course, it may make more sense if the machine was in front of me....I should have brought it home....)

Thanks,
Dante
Click to expand...

Just unplug the connector from the board and place a paper clip on the pins (one in PWROK the other end into COM). That should be how you do it. If it doesn't spin first, then wait for someone else to correct me because I could be wrong.

Since yours is a DA, this diagram may help:
imageEffectsAbove_fw800pinout.png
 
Dcentuori said:
Hmmm. I'm not getting an image for the diagram you posted. Can you try again?

Thanks!
Click to expand...

I just see a blue rectangle.


@128keaton Whenever you post an image from a site, you should first upload it to an image host site (like as an attachment or on Postimage) rather than linking directly to it, because the image may change. Looks like that's what happened here.
 
Just to rule out the possibility of a bad power button, there are alternate ways to power up a DA G4.

One of these is to use a keyboard with a built-in power button. Probably the most common ones are the "compact" keyboards which shipped with the first few generations of iMac(and also with Powermac G3s and other computers until replaced by the Apple Pro Keyboard). The power button on these will work on any G4 tower except for the Mirrored Drive Door models.

The second option is to use an ADC(Apple Display Connector) equipped display. If you look at the video card on your computer, you should have two ports on it, one of which is either a standard VGA or DVI connector, and the other of which is an ADC connector. This looks sort of like a DVI connector, but is wider, has rounded edges, and uses "hooks" to secure the connector rather than screw standoffs.

In any case, ADC displays are powered entirely through the PSU/video card(they only have one cable coming out the back of them). Using a stock G4 card, pressing the power button on the front of the ADC display should power up the computer. Even if it doesn't, the power button will "glow" if the display is receiving +28V from the PSU.
 
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