PowerMac G4 agp tower wont boot up, no screen display but fan's running

Got any loose cards? Check the seating for everything - as what you've got going on sounds like a funky connection somewhere. I can't speak specifically to the model of Mac you have but, the beiges are notorious for things wiggling loose over time. Could be happening to you as well.

Deb.

Hello, I think I am having same problem.

When startup button is pushed, light goes on for a few seconds, then turns off, there is no start-up screen, but I hear the CD-drive operating, after 15 seconds fans go on full power.

I tried disconnected EVERYthing (all hard drives, and CD drives), resat all boards and memory cards, all cables, USB devices and cables.

I tried resetting PMU button, no effect.

If the fans are working and the button momentarily lights, and the CD player operates briefly, does this mean the power supply is working "perfectly"?

If powers supply good, that means mother board needs replacement (I replaced motherboard 3 years ago, but I think different problem)?

Any other ideas???

Thanks in advance,
Terry-t

To all:

Good job on unplugging all periphreals...you should only have the mouse and keyboard connected when troubleshooting. Check all connections in your computer, as far as RAM chips, PCI cards or graphics cards. Have either of you installed or updated anything recently?

Try booting up with the shift key held down, or try booting off of a OS X dvd (put the dvd in and hold the c key down).

Thanks for the ideas MyrkridianRhapsody, but no go. It isn't booting at all.

I found a few apples sites with the following possible solutions that I will try, but my gut is telling me I fried the mother board again. I don't have the money for a new pro-mac, so I hope there is a low-cost mother-board replacement available for my 6 year old mac (any comments?).

Again, if there is someone who has successfully fixed this problem without replacing the motherboard, let me know.

As always, any additional comments/suggestions are welcome.

Will let you know my final solution.

thank you,
terry-t




Power Mac G4: Screen is Black, No Startup Tone, Drive Does Not Operate
The Power Mac G4 computer screen is black. The boot tone is not present, the drive does not operate, but the fan is running, and LED is lit.

This article covers repair procedures for authorized service providers on selected Apple products, but we have published them in the Knowledge Base for the general public for educational purposes. At this time, there are a limited number of repairs that a customer can perform and these are covered under the customer installable parts program http://www.info.apple.com/installparts. If you have not been authorized to perform these procedures, please contact Apple (800-APL-CARE in the USA) or your local authorized service provider to schedule a repair.

Symptom

The Power Mac G4 computer screen is black. The boot tone is not present, the drive does not operate, the fan is running, and LED is lit.

Affected Products

o Power Mac G4
o Macintosh Server G4
o Macintosh Server G4 with Mac OS X Server

Solution

DANGER! This procedure exposes you to high voltages that can result in death or serious injury. DO NOT ATTEMPT THIS PROCEDURE IF YOU HAVE NOT BEEN CERTIFIED AS AN APPLE-AUTHORIZED TECHNICIAN.

1. Power Mac G4 (PCI Graphics): Check jumper block at J25. Make sure jumper is correct color for processor type, includes all required inner metal clips, and is installed in correct direction. See "Processor Module" in Service Source Take Apart for more information.

2. Check video cable/card connections.

3. Reset the Cuda chip. Refer to article 95065: "Power Macintosh G4 (PCI Graphics): Resetting the Cuda Chip"

Solution

Press the Cuda reset button on the logic board to reset the Cuda chip. The Cuda reset button is located to the right of the battery. Note: If the computer still fails to power up, refer to article 95066: "Power Mac G4 (PCI Graphics): Resetting the Logic Board".

4. Reset the logic board. Power Mac G4 (AGP Graphics): Refer to resetting the PMU in article 95037: "Power Mac G4 (AGP Graphics/Gigabit Ethernet): Resetting the PMU on the Logic Board ". If you have a Power Macintosh G4 (PCI Graphics): Refer to article 95066: "Power Macintosh G4 (PCI Graphics): Resetting the Logic Board".

Procedure


1. Unplug the computer.

2. Press the Power On button on the front of the unit.

3. Open the side access panel.

4. Remove the battery from the logic board.

5. Wait at least 10 minutes before replacing the battery.

6. Make sure the battery is installed in the correct +/- direction.

7. Reassemble the computer and test the unit.


Note: This procedure resets the computer's PRAM. Be sure to check the computer's time/date and other system parameter settings afterwards.

5. Reseat video card.

6. Reseat SDRAM DIMMs. Make sure DIMMs are PC-100 DIMMs.

7. Reseat the processor module.

8. Remove all SDRAM DIMMs and try replacing them one at a time to test. Replace any bad DIMMs.

Resetting the PMU Chip Procedure
http://docs.info.apple.com/article.html?artnum=95037

a. 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.

b. 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.

c. 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.

d. Run MacTest Pro and return the computer to the customer.


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

9. Replace video card.

10. Replace processor module.

11. Replace logic board.

12. Replace the power supply.

It is always worth resetting the pram
as well by holding down alt-apple-p-r at the same time immediately after
booting the machine up.

Well let me know what happens after you do all of that, but if you did fry the motherboard then you can buy replacements for pretty cheap. eBay has people selling used ones for around $50-$100 (last time I checked), or you could go for an upgrade. But before you go and buy a new processor, I would try and figure out what's causing it to fry if this has happened more than once...

$50 - $100, that's great news! Thanks for the tip MyrkridianRhapsody!

About three years ago I paid several hundred (400-600? Ouch) for a new motherboard.

From the many forums and sites I've come across, I notice this is a pretty common problem with the g4. It wasn't one of Apple's most competently built products. However, if the board lasts another three years, $100 will be well worth the money spent.

First-things-first though, I will try resetting the PRAM, UCM, FBI, CIA, and the BBC--BB King, etc., before purchasing the board. Perhaps the computer Gods will smile down upon me. Will let U know tomorrow.

Thanks for your assistance,
terry-t

Wow thats alot of money...now with new upgrades you can get processors over 1 ghz for around $200-300. Take a look on ebay, it'd be worth your while.

And as far as the motherboard failures, I'd have to disagree. The G4 tower is a very well built system, and if taken care of, should last longer than 2-3 years. Me and my father have both had G4 towers since they came out, and are still running flawlessly. If you don't often clean out your tower that might contribute to overheating with excess dust. Also if you live in warmer climates that could contribute. Excess heat is not a good thing.

Let me know how it goes.

Also, have you tried swapping out the RAM?

I had this problem with my Quicksilver 2002 twice. I went through all the steps that the other people/Apple suggested. The power supply was good when tested with a meter. I even took it to the Apple store to get it diagnosed the first time. In both cases, it turned out to be dust. The first time, there was dust under the cpu. The store took out the cpu, blew out the dust, and boom, it worked. The second time, I found the dust in the power button. I took off the cover around the button at the front panel, blew it out, and to my relief it worked again. Mind you, the machine didn't look unusually dusty when I opened it up. I hope it works for you. A logic board is outrageously expensive for such an old machine.

There ya go.

Keep your machines clean people!!! Fans can get clogged easily as well. The more dust, the more heat. And the more debris, the higher the possibility for a short across the board. Make sure your heat sink is on properly and is conducting heat correctly. There shouldn't be any dust in your heat sink or near the cpu. Buy a bottle of compressed air and clean regularly or vacuum it out-blowing is not a good idea as your breath contains moisture.

Hey MyrkridianRhapsody,

I briefly tried some RAM swapping yesterday when reseating the cards, but I wasn't 100% thorough in checking all RAM. That is number 8 in the list above, so I will absolutely confirm it isn't the RAM tonight.

Thanks,
terry-t

Dust?

I pray to the computer-gods that this seemingly and potentially expensive complex problem is only common, everyday dust. Will have a go with the forced air tonight. Will let you know tomorrow if it proves successfull.

thanks for the suggestion Ron,
terry-t

Hello,

I tried every home remedy as per the instructions from the Apple site above (including dust removal). Nothing worked. I had to take it into the shop to confirm the problem . . . the processor ($300+ to fix). ****!

It was the logic board three years ago. I notice just from this forum alot of people have similar problems with their G4 too. If I choose to buy another MAC I hope they are engineered a little better today.

Anyways, thank you all for your support, suggestions, and tips. It was appreciated!

terry-t

Wait you didn't have them fix it did you? It's an easy fix that would be cheaper for you to do yourself.

http://cgi.ebay.com/Apple-PowerMac-G4-MDD-1-GHZ-processor-Heatsink_W0QQitemZ2001 19588165QQihZ010QQcategoryZ80031QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Or buy an upgrade for probably close to what Apple is offering to fix it for...

http://www.sonnettech.com/product/encoremdxduet.html

Another user also reported simply taking out his processor and putting it back in fixed the problem...