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G4 MDD Issue....running out of ideas......!

R

Retrosonic

macrumors regular
Original poster
May 13, 2009
107
0
Guys, hopefully someone can help me out. I've been at this for 3 days and I'm not making any progress:

I acquired a G4 MDD Dual 1 Gz processor Power Pc

What happens is this:

When I press the power button, it lites up, then goes off, then slowly lites up again.

I get NO Chime.

I do get Video, but I get the white/gray screen with the rotating little circle. And thats all. It never boots into OSX.

I tried to reset PRAM, but it still went to the white screen. With no chime, its almost impossible to do anyway.

The PRAM battery has been replaced.
Both the little and Huge fans are spinning.
The red lite on the MD is on.
The two fans on the power supply are rotating and pushing air.

The Memory in the box are Two Crucial 512MB DDR 400 CL3 (this is memory I had laying around, it did not come with the pc) MT 200401

I have pulled the battery, reset the PMU button, pulled all cards, memory, etc, to try and reset the box. nothing has worked. I never get a chime. Could no chime be a processor issue?

Based on what I see, I am thinking its the dual processor board that is bad. I can a replacement fairly cheaply on EBAY.

Do you guys think its the processor and NOT the MOBO? Or something else.

ANY help is appreciated!~!

Many thank you for any comments.
 
Has this machine ever worked since you got it?

Can you boot to a CD?

Are you using a ADC monitor?

Is the keyboard responding?

What happens if you unplug the hard drive power and IDE cable completely and power it on? Same thing on the CD IDE cable?

The power button light is normal as is the red light.



The logic board is usually very solid in these machines the processor would be next then memory then the power supply. These are listed from least troublesome to most troublesome. The MDD Powermacs had really flaky power supplies that could cause a wide range of problems.
 
thanks

Hi Classic...thanks for your reply.

Heres are the answers to your questions:

Yes, when I first got the machine, it worked. However, the large fan was NOT spinning. I had it on awhile and then I noticed the video going on and off. I shut down and tried to restart, and got the spinning circles. Is it possible that the fan being dead caused the processor to overheat and it died?

PS...Tonite i replaced the fan with a new one and it IS spinning.

I'm using a small Samsung Monitor.

I cant even TEST the DVD drive because I cant eject the drive to put a disk in. I never get the OS. The paper clip trick would not work either.

As for the keyboard, It doesnt look like its responding at all. Remember , I get no chime.

As for the hard drive, this is interesting...when I unplug the data cable of the hard drive, I get the ? and the tiny square box on the screen and not the spinning little circle. When i plug the cable back in, I get the spinning circle. This would indicate to me that the MOBO is ok.

Do you really think its the Power supply? It seems to be working fine, the fans spin, and the mobo def has power.
 
Retrosonic said:
Yes, when I first got the machine, it worked. However, the large fan was NOT spinning. I had it on awhile and then I noticed the video going on and off. I shut down and tried to restart, and got the spinning circles. Is it possible that the fan being dead caused the processor to overheat and it died?

Do you really think its the Power supply? It seems to be working fine, the fans spin, and the mobo def has power.
Click to expand...

It chimed when it worked last time?
How long you was running it with dead fan?
If you have optical mouse, is it lights up when you power computer?

I don't think that it could be PSU fault (from what you described).
For the now you can:

- reset PMU (google it, if you don't know how to)
- test it with only one memory module
- try another graphics card (if you got one)
- test with Install Disc (or AHT if possible) - to force eject DVD tray click LMB right after you press power and hold it until tray will eject. You can also remove DVD cage and do paper clip trick (will be much easier than with installed)
- try other hdd (if possible with clean OS install done on PPC Mac, not Intel one)

If it all fails, remove CPU heatsink and CPU, inspect CPUs (cores) - look for burns and other physical damages. Remove old thermal paste and apply new one before reassembly.
 
First off you should NEVER run any computer without a system fan. Second is that I know from owning 2 MDD in the past that the 7455 chips in them have a fail safe that prevents them from getting damage due to heat. I believe it's when the CPU core goes above 70 Celsius.
 
Trying

666sheep.....thanks for the suggestions, I've already tried some of them:


reset PMU (google it, if you don't know how to)

>>>>>>I've done this via the small button on the mobo. Nothing happens


- test it with only one memory module

>>>>>>>Did this, same thing


- try another graphics card (if you got one)

>>>>>I do have one from my older G4 and I will try tonite.

- test with Install Disc (or AHT if possible) - to force eject DVD tray click LMB right after you press power and hold it until tray will eject. You can also remove DVD cage and do paper clip trick (will be much easier than with installed)

>>>>>>Ok, I'll try this too.

- try other hdd (if possible with clean OS install done on PPC Mac, not Intel one)

>>>>>>Well, I have two HD, both were installed on PPC mac., not Intel. I could try the other one.


If it all fails, remove CPU heatsink and CPU, inspect CPUs (cores) - look for burns and other physical damages. Remove old thermal paste and apply new one before reassembly.

>>>>>>Ok, I will do that.

If I put a CD in the drive and it DOES boot up to it, what does that tell me, that the hard drive is bad??

Thanks for your help!
Retro
 
if it dose boot from cd then it would mean bad/corrupt hdd, also a trick i used to open the cd drive is to remove the ide cable from the drive (leave the power cable plugged in) then tun the computer on, press the eject button on the drive, the drive should eject, put boot cd in, turn the computer off, plug the ide cable in and turn on the comp while holding the c button
 
retro, good info. I am going to call it the processor.

Reason being I have seen more than a few fail due to overheating.

I was able to restore one though by removing the heatsink and cleaning the processor pad and heatsink with 90% alcohol and a lint free cloth.

I would then apply new silver cpu paste.


That particular machine worked fine after that. What happened was the old paste was rock hard due to overheating and was not doing its job. With the new paste it could cool off just fine.

Keep us updated. If you are trying to save $$$ you could buy a dual 867 cpu for dirt cheap, or bump up to a 1.25 :)
 
ClassicII said:
retro, good info. I am going to call it the processor.

Reason being I have seen more than a few fail due to overheating.

I was able to restore one though by removing the heatsink and cleaning the processor pad and heatsink with 90% alcohol and a lint free cloth.

I would then apply new silver cpu paste.


That particular machine worked fine after that. What happened was the old paste was rock hard due to overheating and was not doing its job. With the new paste it could cool off just fine.

Keep us updated. If you are trying to save $$$ you could buy a dual 867 cpu for dirt cheap, or bump up to a 1.25 :)
Click to expand...

He says in his post that it boots from the lnstal disk so that means the CPU is fine.
 
ClassicII said:
Reason being I have seen more than a few fail due to overheating.
Click to expand...

Me too. Some even quite burnt, especially DP ones.

If you are trying to save $$$ you could buy a dual 867 cpu for dirt cheap
Click to expand...

Yeah, and with a little soldering job (in fact desoldering) you can run it with 1.0 GHz freq. Without this trick, you will get only FSB 133 - like 867 CPU has by default (1.0 DP has 167 MHz FSB). FSB in MDD is set on logic board and CPU daughtercard independently. Both setting must match, if not you will get FSB value that is set on CPU dcard.
 
More Info:

Guys: I want to thank you all for your responses. I was away all weekend, so I will be doing more troubleshooting tonight.

Zen: I did not ever say it boots from the install disk, I said I would try that, but I havent as of yet. Tonight hopefully.

I know the hard drive in there is good, as It came from my older G4 Blue Box.

I have ordered a replacement Dual 1gz processor, so when that comes, The first thing I'll do it install it and see if that fixes things. I wish I had known that the MDD motherboard will accept a dual 1.25 processor!! I would have bought one of those!!!

I have the large fan working now, so the new processor should not overheat.

At this point, I have tried so many things that I truly hope it IS a dead processor. Thats an easy fix. If its not the processor, then its back to square one. Too bad, because I'd really like to get this machine back in action.

More info tonight!!
 
Update 8:30 pm:

Ok, I have put the install disk in the Cd drive and booted up, holding the "C" key. Nothing, I still get the white screen with the spinning disc.

I tried booting into open firmware, no good.

It sure doesnt look like the machine is even
seeing the kyb.

At this point I'm going to wait until the new processor arrives and go froim there. Seems to me it could only be the processor or the mobo at this point!

Thanks for all your help.
 
Retrosonic said:
Ok, I have put the install disk in the Cd drive and booted up, holding the "C" key. Nothing, I still get the white screen with the spinning disc.

I tried booting into open firmware, no good.

It sure doesnt look like the machine is even
seeing the kyb.

At this point I'm going to wait until the new processor arrives and go froim there. Seems to me it could only be the processor or the mobo at this point!

Thanks for all your help.
Click to expand...


Good deal! Dont forget a quick clean and thermo paste :)
 
Update Wed 8:48 PM

Well Guys.......Good news!!

The Machine LIVES!! :)))))

LOL.....had a long day working on this machine, but it is now Rocking and Rolling!!

Installed new PRAM battery, new large fan, the new Dual 1 Gig processor board arrived, I cleaned, applied the paste, and installed that. Powered up...nothing!! By messing around a bit, I discovered that I could NOW boot up to the Cd drive........so I needed to re-install OSX from scratch. Did that, and Bingo!! She lives!

Then I installed a few things from my previous G4, new Superdrive, fast USB card, SATA card and 500 gig drive.

I've got 1 gig of RAM installed, but I've ordered another gig (very cheap) to max it out at 2 gig. Yay for me!!

I'd like to thank all you guys for your help. Your thoughts were invaluable in helping me bring this machine back ..... Many thanks!!

PS...LOL...My old Blue G4 is now a pile of parts, but the funny thing is, I have enough parts to get THAT working again as well. I may do that Saturday and have OS9 on it.

Thanks to everyone!

Retro
 
There is no better feeling than when a system you fear is dead suddenly boot up one day after trying so many things. I have been there.

Great news and I hope the beast serves you well!
 
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