Resurrecting a faulty PowerBook G4 DLSD

Discussion in 'PowerPC Macs' started by max¥¥, Jul 15, 2017.

  1. max¥¥, Jul 15, 2017
    Last edited: Jul 15, 2017

    max¥¥ macrumors 6502a

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    #1
    So just under 2 weeks ago I was sent a faulty PowerBook G4 DLSD by @LightBulbFun, originally we had been hoping to upgrade it with a PPC 7448 that I had ordered on ebay, unfortunatley the seller canceled that sale so that isn't going to be able to happen now. But I thought you guys might find the repair process interesting :)

    This DLSD has 2 faults, one is that the DC in board was faulty, tho other is that is has a liking of kernel panicking.

    Part 1: The mystery of the faulty DC in board:

    I say mystery as I fully expected this to just be a worn DC socket, I have had that a few times on my iBook G3's so expected to have the same fault here, expecting to just have to swap a socket from a spare iBook G3 DC in board I probed the contacts on the back of the dc socket, 23.4v, huh guess the socket is fine then.

    Probing the dc out socket on the board gave me between 1.0v and 3.0v, I tested the input fuse and filter coil expecting one of those to be blown but both came out ok. Next i tested continuity between ground on the board and on the dc in socket and found I had a open circuit, Aha! now I'm getting somewhere.

    I then found if I pushed the probe from my multimeter in to the ground contact on the DC in connector rather hard i started getting a connection, after digging a hole in the side of the DC in connector to check there wasn't a crack in the ground contact I figured there must be a broken ground via to the DC socket.

    One small jumper later:
    IMG_0305.JPG

    We have a PowerBook working on the charger only :)
    IMG_0304.JPG
    The next step is to install Mac OS X on the PowerBook and find out why it is kernel panicking, From @LightBulbFun's testing there is some indications it may be USB related but I need to get a OS installed to be sure
     

    Attached Files:

  2. LightBulbFun, Jul 15, 2017
    Last edited: Jul 15, 2017

    LightBulbFun macrumors 6502a

    LightBulbFun

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    #2
    Awesome to see you where able to track down the fault on the DC inboard, I had probed out the DC in board much like you had and got the same puzzling results, I too originally expected it to be a broken Jack or broken solder joints where someone may of tripped over the cord or a blown fuse, but those where fine as you say

    it was evident there was a break somewhere on the board but i couldn't figure it out like you did :) I wonder if they Via was under a sticker at one point? I remember reading of a TAM CPU upgrade (500Mhz sonnet G3) that died due to a sticker more specify the stickers glue rotting out one of the vias it was over...

    couple notes on the Lobo, some times it will outright refuse to post usually it will refuse to post after being forced shut down from OS X pancing/freaking out over weird stuff going on with the USB bus, when it fails to post what would happen is, I would turn it on, but instead of a chime, nothing would happen and suddenly the fans would kick into full speed, usually turning the machine off and letting it sit for a while i could get it to POST again.

    hopefully your able to fix the Lobo as well :) my money is on something USB related, perhaps the NEC USB 2.0 controller is dying, interestingly, booting Linux on the thing linux would boot disable USB then continue to boot up just fine to a desktop
     
  3. eyoungren macrumors P6

    eyoungren

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    #3
    I would have just replaced the board. My 17s have had several replaced.

    But that's just me. I'm not well versed on doing things like you did.
     
  4. MagicBoy macrumors 68040

    MagicBoy

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    #4
    Erik, in a roundabout way that's kinda what happened. The DLSD Max has was originally bought by me a while ago. Took a gamble on what looked like a good value machine with a bad hard drive. Unfortunately it wasn't - it's the panic happy one that Max has. Kinda balances out @LightBulbFun 's iBook Clamshell of win from the other week. Sometimes you get a bargain, sometimes a parts machine! My hunch was it's something chipset/USB related.

    A few months later I then discovered another DLSD that worked off battery but not mains and acquired that cheap, figuring I could make a good machine out of the two. Swapped the DC board over from the panic happy machine and that's all it needed to make a good working DLSD which is in regular use. @LightBulbFun was interested in the panic happy one, and he's since passed that onto Max.
     
  5. max¥¥ thread starter macrumors 6502a

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    @LightBulbFun The via in question was right next to the connector, no stickers anywhere near it. Possibly could have been drop damage or maybe just old age, we'll never know for sure. And I have had that odd fans and full speed fault a couple of times, in fact, I think it may tell us more about the fault than the KP. If this where a MBP one of the things I would be checking the sensor circuitry, in the DLSD this all connects the the PMU so I might try swapping it out with one from a spare board tomorrow and see what happens :)

    @eyoungren That would be the easy way out :) I do have some spare DLSD boards that may or may not work that I could swap in but that's not as much fun in my books :)
     
  6. MagicBoy, Jul 15, 2017
    Last edited: Jul 15, 2017

    MagicBoy macrumors 68040

    MagicBoy

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    #6
    That was pretty much the conclusion I'd got to. When it did boot cleanly then the internal trackpad/keyboard would stop responding, usually with an error message indicating a USB power irregularity. Same with an external keyboard/mouse. It's not the top case, as I swapped that with the second unit. The panic happy was was rock solid in TDM though. You will have noticed it's not the original logic board for that chassis, so it definitely had a logic board swap at some point before I got it.

    @max¥¥ Glad to see you sorta fixed the DC board!
     
  7. max¥¥ thread starter macrumors 6502a

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    #7
    So this is a real mix of parts then :)

    My original thinking was that the USB 2 controller that was faulty, but that dosen't really fit with the no boot issue, coupled with the fact you seemed to be getting kp's with usb power irregularity's it makes me think it is a current sensing issue and is more likely down to the PMU
     
  8. MagicBoy macrumors 68040

    MagicBoy

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    #8
    Yeah, it had me mildly perplexed and I used to warranty repair laptops many years ago. Some sort of PMU issue would make sense. It was consistently inconsistent!

    I've had zero issues with the DC in board taken from that machine.
     
  9. max¥¥ thread starter macrumors 6502a

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    #9
    looks like my logic was exactly 100%... wrong. USB current sensing is not handled by the PMU but by the usb controller it's self. So it may still be the usb controller. I'll probably try replacing that first even if it dosen't quite fit with the no power
     
  10. max¥¥ thread starter macrumors 6502a

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    #10
    Some progress!

    I have removed the USB controller and the PowerBook Now Boots reliably :) (But using it is quite hard as I can't connect any input devices.... :) )

    However I seem to have created a video issue..... Looks like a GPU reflow / reball might be in order now.
    IMG_0312 copy.jpg
     
  11. MagicBoy macrumors 68040

    MagicBoy

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  12. max¥¥ thread starter macrumors 6502a

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    Nope, The chip looks 100% fine, Just finished soldering a replacement from a dead board so hopefully it should now work :)
     
  13. LightBulbFun macrumors 6502a

    LightBulbFun

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    #13
    Glad to see your making progress with the USB issue :)

    strange on the video issue, have you made sure the LVDS cable is properly seated?/does it show up on an external display? I never noticed any video oddities with the machine while i owned it, and i think video was fine when @MagicBoy owned it, hopefully its just a lose LVDS cable that needs reseating :)
     
  14. max¥¥ thread starter macrumors 6502a

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    Well I seem to now have no usb, Just reflowed the chip to see if that makes any difference

    I don't seem to have the graphics issues any more, might have just been flex in the socket, or just the cable wasn't seated correctly as you said
     
  15. LightBulbFun macrumors 6502a

    LightBulbFun

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    #15
    strange id expect another chip to do something unless its even deader then the last one :D if you can try image/boot an install of OS X that has screen sharing and network sharing installed should let you boot the thing up and control it over the network getting round the no USB issue, I do know that on the 15 inch DLSD the USB chip (along with the wifi card and the cardbus chip) do show up under PCI devices so it would good to check if the USB chip is even showing up there, at least the Graphical issues have buggered off :)

    upload_2017-7-16_17-18-49.png
     
  16. max¥¥ thread starter macrumors 6502a

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    Reflowed it and usb is back :) Just a bad solder job :)

    Except it still had issues, the keyboard and trackpad would work up untill the boot picker list would finish scanning for bootable drives. I had noticed the trackpad flex seemed to have a break in it (it worked at some angles and not others) so on a whim i unplugged the top case. And guess what? Usb works fine now :)

    So it looks like the top case flex probably has a short in it, this may or may not have killed the original chip (I suspect it did as I have had no more boot problems since replacing the chip, with or without the top case plugged in)

    The PowerBook is currently running through ASD to see if that throws anything up, but it's looking good so far :)
     
  17. LightBulbFun macrumors 6502a

    LightBulbFun

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    #17
    Awesome! :D

    The Top case nuking the old USB chip is defiantly plausible, @Gamer9430 had a Bad Top case cable on a White plastic MacBook wreck havoc in OS X (panicking the machine all over the place) but luckily we figured out the issue before it Nuked anything on the logic board
     
  18. max¥¥ thread starter macrumors 6502a

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    Well, it seems the issues run deeper, after running for a while the issues came back. Resetting the PMU seems to clear them for a while so I am in the process of replacing that but I hate soldering tqfp chips (i'll take a bga chip any day over a tqfp :) ) the chip is on but i have a couple of pins that got bent into each other in the process. I'm too tired to focus on the legs of the chip now so this powerbook will have to wait for another day now
     

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