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Yiannis Author

Level 1

99 points

Power Mac G4 MDD strange startup problem

Hello ,

I have an old G4 MDD dual 1Ghz which is been used by my 6 years old son for gaming and watching movies.

I had Tiger 10.4.11 on a IBM deskstar HDD and Leo 10.5.8 on a seagate HD.

Everything was fine until some days ago, when my mac didn't boot from the first try…..black screen.

After a second attempt , booting was just fine.

I have now two system disks (IBM deskstar HDD) with 10.5.8 installed.

Mac is not booting always from first attempt….it takes two more with or without the option key pressed to choose a startup disk.

I have done all the usual…….reset PMU-PRAM…replacing battery,replacing cables,cable select the drives and now forced one to master and second to slave.

I have run Service Diagnostics 2.1.5………..ALL TESTS PASSED.

Still not booting normally….

Any suggestions please??

Thank you all!🙂

PS:It is also loosing very often internet connection via ethernet……..I think it's not a router problem as all my other macs are working normally.

PowerMac, Mac OS X (10.5.8), 2g Ram-1GHZ MDD

Posted on Oct 6, 2014 10:24 AM

75 replies

BDAqua

Level 10

239,363 points

Dec 1, 2014 10:51 AM in response to Yiannis

OOPs, long thread, forgot it's an MDD here! 😊😕

Long shot, but since it's a common G5 problem, might be worth a try...

If you're sure the RAM is good, try the Hair Dryer trick...

http://discussions.apple.com/message.jspa?messageID=13240047#13240047

https://discussions.apple.com/thread/3061091?answerId=15223603022#15223603022

https://discussions.apple.com/thread/2620983?answerId=15499912022#15499912022

https://discussions.apple.com/thread/3175959?answerId=15613068022#15613068022

https://discussions.apple.com/thread/3270112

https://discussions.apple.com/thread/3287993?answerId=16053892022#16053892022

No power light at all...

https://discussions.apple.com/thread/3692775?tstart=0

It can show on any G5, and even many other computers & electronic devices of the period.

http://www.macintouch.com/reliability/pmg5.html

http://lowendmac.com/ppc/power-macintosh-g5.html

And see this last one in particular...

https://discussions.apple.com/thread/3507385?answerId=16781690022#16781690022

Heat gun better...

https://discussions.apple.com/thread/3916312?tstart=0

Yiannis Author

Level 1

99 points

Dec 3, 2014 8:48 AM in response to BDAqua

Are there any more ideas guys?????

BDAqua

Level 10

239,363 points

Dec 3, 2014 11:08 AM in response to Yiannis

Whew, long tread, can you summarize what we've tried so far?

And with no drive you could boot to Open Firmware on power up?

Yiannis Author

Level 1

99 points

Dec 3, 2014 11:18 AM in response to BDAqua

Please take a look at three answers of mine just before your previous answer.

🙂

ps: when the keyboard its not working ,no can not.BTW the keyboard is fully working but when my mac don't startup properly I get no usable power at the usb ports.

Dec 3, 2014 1:30 PM in response to Yiannis

Not really, but one set of things you said didn't quite make sense or maybe I just need clarification:

You stated:

Here is a strange observation…When I hit the startup button and I don't hear the HD to spin ,I remove the ribbon cable from the disk right after the chime and put it quickly back.Then the HD is spinning and the G4 booting up normally.

but subsequently:

With no disks attached there is nothing on the screen…no question mark..nothing.

So if the disk is attached at startup and you detach and subsequently re-attach it quickly after the chime it will start up, but if they are detached at the start, then nothing happens after the chime? What about if the disks are detached at the start and then you plug them in quickly after the chime?

Regardless, it seems that the fault would have to be either in the power supply to the disk, the disks themselves, the cable, or the disk controller (but that's on the logic board), and only the latter makes sense if nothing works with everything detached (I assume you have disconnected the drives at the logic board, not at the disk).

Thinking about this, I just realized I'm also not clear which cables are detached and where from the drive when you say the disks aren't attached. Are you detaching the poiwer cable, the IDE cable, or both, and in the case of the IDE cable at the drive or at the logic board? It would be interesting to know if the disks spin up if they are powered but the IDE cable is detached at the logic board; I would like to know, as well, if the disks spin up when you attach external power, both with and without the IDE cable attached at the disk end (don't even need to try to boot your machine for the last set of questions).-kby

Yiannis Author

Level 1

99 points

Dec 8, 2014 7:11 AM in response to Kimo B. Yap

Here is more info if this helps………

1) What I said before about the computer startup after I re-attach the ribbon cable to the disk is …...negative….

2) No disks and no cords in the computer does not do anything most of the time……..no "question mark".Some times it appears too.

3) Having the power cord to the disk and attach the ribbon cable to the disk works but not always.

4) After I manage to startup the computer using the above method and try to restart the disk was spinning but there was a black screen again.

5) Using external power and having the ribbon cable attached to the logic board does not let the disk spin.

If I remove the cable from the logic board the disk is spinning.The same happens if I have the cable connected to the disk only.

The same happens if I use internal power to the disk.

BDAqua

Level 10

239,363 points

Dec 8, 2014 10:10 AM in response to Yiannis

It sounds like there is a short on the logic board & voltage is getting to the IDE cable.

Yiannis Author

Level 1

99 points

Dec 8, 2014 10:15 AM in response to BDAqua

Is it fixable??

BDAqua

Level 10

239,363 points

Dec 8, 2014 10:39 AM in response to Yiannis

Not very likely, but you could closely inspect both sides for say bulging Capacitors or burnt components.

Yiannis Author

Level 1

99 points

Dec 8, 2014 10:50 AM in response to BDAqua

Are there any specific capacitors or components to look for???

There about 20 capacitors I can see right now……..😮

BDAqua

Level 10

239,363 points

Dec 8, 2014 11:03 AM in response to Yiannis

Could be any of them, or several, as memory serves me there were bogus Capacitors on the supply chain about that time.

If you have a multimeter might check out my theory on the voltage...

http://pinouts.ru/HD/AtaInternal_pinout.shtml

Yiannis Author

Level 1

99 points

Dec 8, 2014 11:29 AM in response to BDAqua

Well..I am not an expert but if you guide me I could check the pins………but I don't know how to start….sorry..😊

BDAqua

Level 10

239,363 points

Dec 8, 2014 12:49 PM in response to Yiannis

Well, with the meter connected to ground, just check every pin for AC or DC voltage when power is on.

Dec 15, 2014 6:41 PM in response to kahjot

kahjot wrote:...If that's the issue, you will have to decide whether it's worth spending any money to fix it. I have no idea what power supplies go for these days....

I just replaced the PSU in my machine, it was having trouble starting up. This eBay seller will refurbish one that you ship to him, or you can just buy one that is already refurbished and a return shipping label is included to ship back your old one for $20 credit. Not sure if this is your problem or not, but I am a pretty satisfied customer here:

http://www.ebay.com/itm/Apple-PowerMac-G4-Mirror-Drive-Doors-Power-Supply-REPAIR -SERVICE-MDD-/141030901102?pt=LH_DefaultDomain_0&hash=item20d618c56e

kahjot

Level 4

2,462 points

Dec 16, 2014 7:10 AM in response to Glen Doggett

That's a good resource, if you absolutely have to keep your MDD alive.

Power Mac G4 MDD strange startup problem