Something just Fried in my Pismo

Discussion in 'PowerPC Macs' started by bunnspecial, Mar 21, 2015.

  1. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    Okay, not sure what's going on here, and I'm hoping someone might have some idea before I dig into it and find out what's going on.

    For background:

    500mhz G3(stock)
    1gb PC-133
    Mostly dead battery in left hand bay
    DVD-ROM on the right

    I had it booted into OS 9, and it was running fine. I was preparing to attempt to install OS X Server 1.0 onto my GigE via TDM. I had the GigE booted into TDM.

    As soon as I connected the FW cable to the Pismo, I heard a pop and "let the smoke out" of something. The computer turned off, and it got VERY hot on the bottom, near the Apple logo on the bottom and just a little behind the FW ports.

    I pulled the battery and unplugged it. After a few minutes, I got brave and tried powering it on again. The computer chimed, and the screen flashed gray for a moment before going blank. I heard something that sounded like sizzling, accompanied by the same spot on the bottom getting warm. I immediately powered it down again. I also heard the hard drive spinning.

    I'm thinking(and hoping) that maybe I just popped a cap and can repair it. The fact that it powered on and chimed is encouraging.

    Without tearing into it and pulling the logic board, does anyone have any thoughts as to what I might be dealing with? I may try tearing it apart this evening just to see if I can get a visual diagnosis.
     
  2. Gamer9430 macrumors 68020

    Gamer9430

    Joined:
    Apr 22, 2014
    Location:
    Central New Jersey, USA
    #2
    Damn. I wonder if I should be concerned by the hot spot of the bottom right corner of the monitor on my Wallstreet. Under the plastic on the bottom gets extremely hot. I'm not sure how fast it gets hot, but when it's hot, it's most likely 100+ degrees.
     
  3. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
  4. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #4
    Given how it sounded and smelled, I figured the problem would be pretty obvious if I took the computer apart.

    I wasn't wrong-I did indeed pop a capacitor-C184 to be exact. I'm guessing after it popped, it shorted and that's what caused the bottom to get so hot. It left a nasty burn mark on the bottom of the case, too, although fortunately nothing came through.

    If I knew what value it was, it would be a pretty straightforward repair. If some kind soul on MacRumors has a Pismo logic board lying around and could either read or measure the capacitance on C184, I'd be enormously grateful.

    I'm also wondering what the consequences of simply removing the capacitor would be. Since it popped when I plugged something into the FW port, I'm guessing removing it might leave me without Firewire.

    C167 and C121 are both the same, and appear to have the same dimensions as the blown one, so I suppose I could also go off the assumption that the blown one is the same as these two.

    Of course, I could also just swap the logic board, but a search on Ebay didn't turn anything up and I'm really just not inclined to do that if the current one can be salvaged. Given that it still chimed even with the blown cap, I'm guessing that's a possibility. Fortunately, it doesn't appear to have taken out anything else.

    Our scientific instrument tech at school owes me a bunch of favors many times over, so I could always just take the board to him and ask if he would sort it out, although I'd really like to do it myself.

    It's a shame that it appears beyond the point where I can simply refill the magic smoke that I let out:)
     

    Attached Files:

  5. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #5
    I spent some time looking at the board, and it seems as though all the caps of this size and shape carry the code ∆107A. A little bit of internet searching leads me to the 107 code being a 100µF tantalum surface mount capacitor. The "A" refers to the size(3.2x1.6mm).

    I just need to figure out the correct voltage rating, and either find them on Ebay or put in an order with DigiKey. Maybe I'll get lucky and the instrument tech at school will have some...I'll have to check with him on Monday.
     
  6. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #6
    I ordered some capacitors from China, but didn't want to leave the computer taken apart for two weeks while I wait on them(that's a LOT of screws to keep straight).

    So, I figured I had nothing to lose by going ahead and removing the shorted cap from the board.

    I put the thing back together, pushed the power button, and held my breath. It seemed to take it a few minutes, but finally it chimed and then booted!

    I haven't tried plugging in a FW device, but at least FW still shows up in system profiler.

    I'm not calling it fixed yet, but at least its working, and the tear down to the logic board isn't too terribly bad on this computer.

    If nothing else, I'm at least going to repaste the CPU. I did it several months back when I upgraded the RAM(taking these all the way to 1gb requires removing the CPU) but figured the relatively cool G3 would be okay at least for testing with the old, well cured AS5 left in place.
     

    Attached Files:

  7. weckart, Mar 22, 2015
    Last edited: Mar 22, 2015

    weckart macrumors 68040

    Joined:
    Nov 7, 2004
    #7
    Bunn, you cannot use the Pismo as a helper to install Server 1.x. The server uses a helper MacOS volume in the Install disc to aid partitioning and to send nvram instructions to OF so that it can reboot into the UFS installer and recognise the newly created UFS volume on your HDD.

    The server itself lacks the hardware drivers to run on a Pismo. The Pismo needs MacOS 9.0.4 as a minimum, which came with Server 1.2. I think Server 1.0 used 8.6 as a helper, which the Pismo will not boot. You will need either a Kanga, a Wallstreet an iBook Clamshell or a Lombard to install and Server 1.x does not support FW so FW target mode is out.

    Check rhapsodyos.org for ideas. Server 1.2v3 is the only one that will run on a G4, btw. All the others are limited to G3 processors, although a 604 works too without Bluebox.
     
  8. bunnspecial, Mar 22, 2015
    Last edited: Mar 22, 2015

    bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #8
    I know you told me that it wouldn't work, but I sometimes I have to touch the hot stove despite being warned :rolleyes:

    In any case, I'm not sure why plugging in the FW cable popped the cap. At least no permanent damage(seemingly) occurred.

    BTW, I was able to get the Server Installer to boot on my GigE, although it hung at the "OS X Server Installer" splash screen with a spinning pinwheel. That at least was encouraging, so I'm trying again now with 128mb of OEM PC-100 Apple RAM(I pulled it from a B&W I upgraded) and a Rage 128.

    BTW, the server installer is interesting, although I'm sure this is old news to those of you who have played with it before. The install disk actually boots into OS 9, then the installer is run-you select the install volume, and the computer reboots into the Server installer.

    My only Clamshell has FW, so I suppose that's out as an install aid.
     
  9. Gamer9430 macrumors 68020

    Gamer9430

    Joined:
    Apr 22, 2014
    Location:
    Central New Jersey, USA
    #9
    I've had some odd experiences with FW 800 on my MBP. Once I accidentally hit the port with a paper clip, and it sparked and my computer shut off. Another time, I was trying to plug something into a USB port and hit the FW800 plug and again the computer shut off. I have been extremely careful not to touch anything metal to the FW port since then. I have no clue why it did that, but I don't feel like testing it again, lol.
     
  10. weckart macrumors 68040

    Joined:
    Nov 7, 2004
    #10
    Just make life easier for yourself and grab 1.2v3. That should install directly onto any PM G4 older than a DA. I have only done this with PowerBooks and needed to keep the install partition to no more than 8 GB and within the first 8GB of the HDD. You should be able to install onto the Clamshell but I could never get it to work for me - it just refused to see a HDD to install upon.

    The only time I tried networking over FW I got sparks but luckily no damage. I leave FW well alone now. In any case rhapsodyos.org is a must-read. It will save you hours of head- scratching. Rhapsody is a bit of a Frankenstein OS but watching OS 8.x booting in a virtual machine (Bluebox) within Rhapsody once it is up and running is well worth the effort.

    I have my eye on a B&W tonight being sold locally. It is the prime supported machine for Rhapsody and the DPs. PowerBooks are too finicky.
     
  11. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #11
    I've just started reading at Rhapsody.org. There's a lot of info there, but will spend the afternoon reading.

    In any case, I was trying to install 1.2v3(I think-it's the PPC one that's on Macintosh Garden), and it seemed to be at least on the right road to success. It just wouldn't get past the splash screen. I hope that the Rage 128 and minimizing the RAM should help me get further.

    I have another B&W that I haven't done anything with, so I'll give the DPs a try on it.

    I've actually used Firewire between systems a LOT-this is the first time anything like this has happened. I'm just happy that it didn't cause any permanent damage.
     
  12. catzilla macrumors 6502

    catzilla

    Joined:
    Dec 15, 2013
    Location:
    Rhode Island
    #12
    I would check that cable, it sounds like there was a short that took out the cap.
     
  13. jantoman, Mar 24, 2015
    Last edited: Mar 24, 2015

    jantoman macrumors newbie

    jantoman

    Joined:
    Mar 2, 2014
    Location:
    Italy
    #13
    capacitor value

    Right now my Pismo lies open on my workbench... it doesn't start anymore. I desoldered and measured C184 capacitor with a component tester I got from eBay, because there's nothing written on it: it reads 10.000 nf (10 microfarad), quite uncommon for what it looks like a polyester, non-polarized capacitor. I guess it won't be an easy task to find it, but I wish you the best of luck, of course. I guess it acts as a filter, anyway: you can go on without it, as you already discovered ;-)

    I started another topic about my Pismo: if anybody is interested, here is it:

    http://forums.macrumors.com/showthread.php?p=20880720#post20880720
     
  14. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #14
    Thank you so much for doing this-I just wish I know why it happened in the first place!

    The FW400 cable I'm using seems to be very high quality. It has thick, clear plastic insulation and a braided cover around the data wires. The connectors have plastic tips to help avoid any shorting while inserting the cable.

    I've used this cable many times-both in TDM and and to connect external HDDs, and never had an issue with it.
     
  15. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #15
    Well the Firewire port voltage ranges from 12 volts to 30 volts and the maximum power is 30 watts so that's quite a lot :D
     
  16. Gamer9430 macrumors 68020

    Gamer9430

    Joined:
    Apr 22, 2014
    Location:
    Central New Jersey, USA
    #16

    Yea. I remember now that it wasn't a paperclip, but the headphone plug. It was just very odd that it grounded to the USB and headphone plug. I should google if anyone else has this issue...
     
  17. ctmpkmlec4 macrumors 6502

    ctmpkmlec4

    Joined:
    Jul 4, 2014
    Location:
    Lyons, KS
    #17
    Does your Mac have a CD or DVD drive? I had issues installing it on my GigE until I reinstalled all the original hardware. I had to reinstall the CD-ROM and the Rage 128. The Rhapsody installer is super picky. Oh, and if you're using a display with the ADC connector, you will not be able to use the USB ports on it. Use only the USB ports on the tower itself. If you have a SCSI card installed, remove it, too.
     
  18. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #18
    Yes to all-DVD +/- RW, GEForce 2MX Twin-View connected to an ADC display, and a SCSI card.

    I'd tried it with the Rage 128 and SCSI removed, but didn't go to that extent to downgrade it.

    Do I need an OEM Apple CD-ROM or will any generic CD-ROM(only) work? I'm not sure if I have any working OEM CD-ROMs-I may need to borrow one out of a beige G3 if that's what I need to install it.
     
  19. ctmpkmlec4 macrumors 6502

    ctmpkmlec4

    Joined:
    Jul 4, 2014
    Location:
    Lyons, KS
    #19
    I can't answer that. The one I used is an Apple shipping drive. I can't see why a generic CDROM wouldn't work.
     
  20. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #20
    Thanks-I might dig out an OEM one out anyway just to get rid of any possible variables.

    My first Digital Audio came with an OEM CD-ROM drive, and it got transplanted into a beige desktop because the drive in was dead. That particular desktop is not used very often(I prefer my upgraded one with a 400mhz processor), and is missing the CD-ROM bezel so I can probably yank it out without even taking the computer apart :).
     

Share This Page