G4 MDD won't boot up - CPU fried?

[LimeiBook86]

So I picked up this G4 Dual 1GHz MDD tower yesterday for under $50. It had no HD, RAM, or Video card. So without that all it wouldn't boot, the LED power light would go on for a sec, but nothing. So I rearranged the power-on board (it was unscrewed) and the machine sprang to life, fans spun, but not startup tone. I put an AGP card in from an older G4 and put in a stick of DDR RAM, popped in an IDE drive and tried again.

Still the fans will whirl up, but no video or startup chime. I took apart the heatsink since I saw 1 screw missing. The CPUs looked a bit odd - do you think they are damaged? One sort of looks burnt so maybe it is. Looks like there was no thermal paste left on them. Do you think the CPUs are fried or do I have another issue?

Here is the photo I took of both of them: http://stevenmatarazzo.com/photos/G4-CPU.jpg

Thanks!

-Steve

 

[Strimkind]

Sounds odd for the CPU but usually if everything else is good and you have a bad CPU you get a few dings or beeps...or something like that. I suspect that it is more related to the PSU on the MDD which are known to have problems after a few years. Usually past the Applecare warranty. Try testing the PSU with a multimeter and see if the voltages are correct. If that is good, then you may want to have a closer look at the motherboard and CPU.

 

[jruschme]

So I picked up this G4 Dual 1GHz MDD tower yesterday for under $50.

Just curious... I notice that your location is NJ. Was this the $35 one at the TCF flea market?

John

 

[mac-man6]

I would say your problem is the CPU, if you replace the CPU you still may have quirks in the system but it will boot. It's odd because I had the exact same issue before Xmas.

Check out this link, http://68kmla.org/forums/viewtopic.php?f=13&t=11749 you'll see a pict I took of my burnt out processor. It looks like the same processor out of the pair burnt out. The white border around the processor is supposed to be the same colour in both pictures in the corner the white has been turned brown or rust coloured. I bet if you look at the underside of the heatsink you'll see some of that colour transferred to the heatsink. 1 of 2 of those processors is pooched.

I replaced the CPU daughtercard and was able to get a working machine. If you have a dual 1.0ghz you should be able to swap cards from another dual 1.0ghz, a single 1.25ghz and probably a dual 1.25ghz.

If you read through this posting you can see the problems I still have http://68kmla.org/forums/viewtopic.php?f=2&t=13414

 

[LimeiBook86]

Yes I did get the tower at the flea market, I didn't pay $35 however, I got it as a bundle with a few other items.

Thanks for all of your information and help, you've confirmed my fears that it was the CPU. I don't know if it's worth it for me to get the CPUs replaced, they're about $50 on eBay... it's a nice machine but I got it to replace my QuickSilver and I don't think putting more money into it will be worth it. I'll just keep the QuickSilver around for now I suppose.

Too bad it's the CPUs that were damaged, I should have known when I saw one screw missing from the heatsink. At least the PSU still works, I see that going on eBay alone for $90-$130.

Thanks

 

[mac-man6]

There's two models, one that's been recalled and the one replacing it. If you got a Samsung PSU I think you're good. I still think they're great looking computers.

 

[Paralel]

Interesting. Was the cause for the processors burn outs ever elucidated? I've salvaged some 1st gen Pentium systems that are 17 years old and I've never come across a CPU that burned itself out as a result of dried up thermal paste, etc... These G4 system seem too young for it to be due to just simple age.

 

[LimeiBook86]

I'll check the PSU brand when I get a chance.

I have no idea what the previous owner did to the machine. One screw on the heatsink was missing and it looked like there was no thermal paste at all. Pretty sure it's a dead CPU... Although, I found if the startup button board isn't in the right spot the system LED will only light for a second and tye system will not even start. However this may be a loose connection or wire on that section itself. I did smell a bit of an electrical smell... But I could not track down where it was coming from. Would be a shame if the CPU burned up right in front of me. :O

 

[MacJunky]

I have no idea what the previous owner did to the machine. One screw on the heatsink was missing and it looked like there was no thermal paste at all.

I bet he was screwing around and just did not know what he was doing or heard about the early macbook pros having too much and thought he would 'fix' his G4 as well. *disappointed rolleyes*

Although, I found if the startup button board isn't in the right spot the system LED will only light for a second and tye system will not even start. However this may be a loose connection or wire on that section itself. I did smell a bit of an electrical smell... But I could not track down where it was coming from. Would be a shame if the CPU burned up right in front of me.

I am not sure how the front panel board is mounted on the MDDs but next time you have it out look to see if there is any metal contacting odd areas of it or wires poking around the wrong places. It sounds like a short.(if it completely dies right after)Look for damage to it's cable as well.

Oh, and Paralel. I had a 700MHz eMac here that was overheating with the stock paste...Well, it was not paste anymore. Took 10 mins to scrape that old crap off then put on some new stuff and it worked fine.

 

[CJ_Miller]

Got to be careful with MDDs, they run extremely hot. But they are excellent machines, well worth fixing to keep in service. Running at less than 1.25GHz helps a lot. My 1.42 dual was regularly about 150 degrees Fahrenheit inside, with fully functional cooling. A 1GHz shouldn't waste so much power.

 

[LimeiBook86]

Well I sold the machine for the same price I paid, so that person is going to play with it now. I was honest and explained the problems to the best of my knowledge. Thanks for the help!