Is this processor toast? (pics)

Discussion in 'PowerPC Macs' started by flacens, Aug 21, 2013.

  1. flacens, Aug 21, 2013
    Last edited: Aug 21, 2013

    flacens macrumors newbie

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    Nov 20, 2007
    #1
    So a few weeks ago, I tried turning on my mac and the screen stayed black, and the fans just started going crazy. Haven't been able to get it to boot since. The computer will turn on, but within 15 seconds a red LED on the motherboard stays lit and then 30 seconds later the fans go crazy.

    I've taken it all apart, cleaned it with an air gun, put it all back together, tried using good ram in different match slots and no luck.

    I'm assuming now its the processor. Can anyone tell by these pics if my processor is bad?

    It's a dual core, single processor (I think) 1.8 ghz G5 btw

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  2. alexrmc92 macrumors regular

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    Feb 7, 2013
    #2
    I'm assuming thats thermal compound and not smoke residue. Is that line in the middle of the die a crack?

    Other than that it looks normal
     
  3. flacens thread starter macrumors newbie

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    Nov 20, 2007
    #3
    No, I don't believe it's a crack, just like a scratch on the white stuff.

    But if you look at the first pic, on the bottom-left part of the processor you can see a white hairline crack that originates from the processor and goes off onto the circuit board....i'm wondering if thats maybe a short or something?

    thanks for your response too
     
  4. Swampus macrumors 6502

    Swampus

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    #4
    Did you redo the thermal compound when you put it back together? Also, did you get a start-up chime?
     
  5. flacens, Aug 21, 2013
    Last edited: Aug 21, 2013

    flacens thread starter macrumors newbie

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    #5
    ummmmmmm....

    not sure what thermal compound is, and i haven't put it back together yet. I'm debating whether or not to buy a new processor on ebay

    also: no I did not get a start up chime...
     
  6. Swampus, Aug 21, 2013
    Last edited: Aug 21, 2013

    Swampus macrumors 6502

    Swampus

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    #6
    Thermal compound completes the thermal bond between the CPU and the heatsink. It's the dried pasty stuff in your pictures. The old stuff needs to be cleaned off and new stuff applied. A lot of us here like MX-4.

    You cannot even put the old CPUs back in to test without doing this. Glad that you haven't. I misread your original post.

    You will need fresh thermal compound even if you get a new CPU from eBay, so might as well get some now to see if it will boot with you old CPU (it's also possible that the problem isn't CPU related. See here for some G5 troubleshooting guidelines).
     
  7. eyoungren macrumors P6

    eyoungren

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    #7
    I had your exact same symptoms a few months ago with my work G5. In my case it was the logicboard/processor. I took the Mac home, my boss replaced it with a Mac Pro and I bought a new logicboard with cpu on eBay for $50.

    G5 came right back up and works just fine now.
     
  8. Swampus macrumors 6502

    Swampus

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    #8
    I think that's good advice. Given that the memory has already been swapped around, what's described here normally points to a logic board problem. If you can find a good deal on a logic board / CPU combo, that might be the way to go.
     
  9. flacens thread starter macrumors newbie

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    Nov 20, 2007
    #9
    Wow, i guess that's worth a shot before diving into buying a new mac. I'll def look for new logicboard + processor and see if i can find a match.

    Thank you guys for your help and responses! I automatically assumed it was the processor and didn't really even consider it could be the logic board.

    Thanks again
     
  10. eyoungren, Aug 21, 2013
    Last edited: Aug 21, 2013

    eyoungren macrumors P6

    eyoungren

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    #10
    Well, to be honest, it could have been either one. I came in to work to find the fans revved and the G5 frozen. Our server had restarted, which is always a sign here that there was a power failure. I made educated assumptions that the power failure probably fried the board. Pretty good bet if that was the case that it took the CPU out too.

    So, whether it was the CPU or the logicboard, both got replaced. Honestly, while I am comfortable in doing work inside Macs, going as far as to pull the CPU out and then trying to find the right chip only to discover it was the logicboard, or the other way around just wasn't what I was willing to do at the time.

    Someone had a logicboard, cpu, heat sink combination for my model (1.8Ghz, single processor, late 2004) for $50 so I ran with it. Turns out that combo was from a US made G5, a bit earlier that the one it replaced, but so far I have had zero issues. Why mess around when $50 or so will solve your problem?

    EDIT: The biggest problem I ran in to was trying to find instructions on dissasembly. Turns out that my particular model seems to have a dearth of instructions on the web. There was a lot of info for the old 1.6ghz and the dual 1.8ghz processors, but I ended up having to resort to a hard to find third party tech manual I found on an Australian Mac repair website.

    Getting the damn cover off the heat sink was the worst part. It involved a screw hook in order to get the plastic rivet pin out!
     
  11. flacens thread starter macrumors newbie

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    #11
    Yeah i hear they can be quite tricky to disassemble but i have mine practically stripped down to just the logic board already! Luckily i found this small screwdriver with an extension that fit perfectly to get those screws off the heatsink.

    I hope i can find a matching logicboard and processor!
     
  12. flacens thread starter macrumors newbie

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    #12
    I found the processor with the heatsink on ebay and i also found the logic board on ebay.... not sure which to purchase first...any ideas?
     
  13. eyoungren macrumors P6

    eyoungren

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    #13
    I don't know what to tell you. I bought mine all as one unit. I was trying to avoid purchasing a cpu and a logicboard and then having to put it together.
     
  14. alexrmc92 macrumors regular

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    #14
    How do you know anything is bad? have you replaced the PRAM battery?
     
  15. flacens thread starter macrumors newbie

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    Nov 20, 2007
    #15
    Is that the thin, little coin shaped battery?

    EDIT: just googled it...no i have not replaced it but im reading that it really only stores a few parameters in it like the date and clock info
     
  16. cocacolakid macrumors 65816

    cocacolakid

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    #16
    Normally if the PRAM battery is dying/goes dead, first it starts giving you oddball problems, and you notice the date/time are incorrect. Then once it dies the Mac won't boot. I've never had one that had the fans spin up with a black screen. The PRAM battery is pretty cheap, $5-10, so it might be worth trying and replacing it anyway since that Mac is already 7 years old or maybe older. PRAM batteries usually have a 10 year lifespan, supposedly, at least the half AA type.
     
  17. Sepultura macrumors regular

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    Jul 10, 2013
    #17
    Thermal paste is the gray crap in the middle of the CPU. You should reapply new compound when you take it apart.

    My Quad G5 doesn't work and it has come down to 2 things.

    1. Motherboard
    2. One CPU is dead

    In open firmware type

    setenv boot-args cpus=1
    reset-all

    That will disable one of the CPUs. If you have the same problem, swap the CPUs and try again. That's what I need to do.

    If that is not the problem then it's your motherboard.
     
  18. eyoungren macrumors P6

    eyoungren

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    #18
    Just curious. How can the OP get to open firmware, if when he turns the Mac on all he gets is a black screen or no video at all?
     
  19. Swampus macrumors 6502

    Swampus

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    #19
    And we're already talking about a single CPU machine, aren't we?
     
  20. Sepultura macrumors regular

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    Jul 10, 2013
    #20
    Woops my bad.

    I been seeing so many G5 topics pop up the last few days. Skimming the threads late at night doesn't help. :eek:

    I can't help with the black screen, but I have the other symptoms. Notorious LED and airplane fans...

    You can try a heat gun on the ram sockets or baking the motherboard itself if your up to it.
     
  21. flacens thread starter macrumors newbie

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    Nov 20, 2007
    #21
    It's fixed!!!!

    So i installed the new processor and heatsink from ebay and powered it on and whaddya know....*startup chime*...music to my ears!!

    Sure enough it powered on and is back to life, 100% functional again!!! many thanks to eyoungren for that advice!!

    FYI: didn't replace PRAM battery
     
  22. eyoungren macrumors P6

    eyoungren

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    #22
    Awesome! Glad to hear it's all good!
     

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