iMac G5 wont start

Discussion in 'PowerPC Macs' started by JoyBed, Jul 23, 2019.

  1. JoyBed macrumors member

    JoyBed

    Joined:
    Jun 14, 2019
    #1
    Hi folks! I finally got something with a G5(I know i wanted a PMG5 Quad, I am still searching for one). Its a iMac G5 this one https://everymac.com/systems/apple/imac/specs/imac_g5_1.8_20.html with 2 gigs of ram installed. The thing is it was for sale as "for parts/repair". When I try to turn it on the light in the down right corner lights up and just the diagnostic LED 1 and 2 are lit up. No backlight, no fans, no sound, no nothing... First thing I noticed are the caps on the boards. Any other idea?

    image2.jpeg image3.jpeg image1.jpeg
     
  2. Raging Dufus macrumors 6502

    Raging Dufus

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    Aug 2, 2018
    Location:
    Kansas USA
    #2
  3. sparty411, Jul 24, 2019
    Last edited: Jul 24, 2019

    sparty411 macrumors regular

    sparty411

    Joined:
    Nov 13, 2018
    #3
    I can see bulging caps in your pictures, like you said. Replace them, then go from there. In my experience, replacing bulging caps solves no boot problems roughly 90% of the time.
    --- Post Merged, Jul 24, 2019 ---
     

    Attached Files:

  4. JoyBed thread starter macrumors member

    JoyBed

    Joined:
    Jun 14, 2019
    #4
    So far I replaced all the caps in the power supply and these six on the mobo. The error persists. I cant source the other caps in my local shop or in my work. Sorry I forgot to take a picture of the PSU.

    988A4FD3-0380-4938-8E2C-3037B69D64A8.jpeg
     
  5. Eriamjh1138@DAN, Jul 24, 2019
    Last edited: Jul 24, 2019

    Eriamjh1138@DAN macrumors 6502a

    Eriamjh1138@DAN

    Joined:
    Sep 16, 2007
    Location:
    BFE, MI
    #5
    You still have some bad caps to the left of the G5 Heat sink in the first pic. Replace all of the caps of any type if a single one of them is bulging.
    You can buy caps from mouser.com, digikey.com.
     
  6. sparty411 macrumors regular

    sparty411

    Joined:
    Nov 13, 2018
    #6
    I counted 13 bulging caps on the main board. I highlighted them in your pic I edited.
     
  7. JoyBed thread starter macrumors member

    JoyBed

    Joined:
    Jun 14, 2019
    #7
    Dont worry I see them, but as an electrical engineer I dont trust even the good looking ones that are parallel to the bad ones. So its 18 to replace without the 6 I already replaced.
     
  8. tigerintank macrumors regular

    Joined:
    Jun 16, 2013
    #8
    You can swap the iMac PSU for a standard PC PSU with some pin swaps in the connector. Iirc there's a post on this sub forum somewhere
     
  9. Eriamjh1138@DAN macrumors 6502a

    Eriamjh1138@DAN

    Joined:
    Sep 16, 2007
    Location:
    BFE, MI
    #9
    JoyBed asked for a pics of my mobo questioning missing caps. It is not uncommon for some components to not be populated in final production.

    Here's my 1.8GHz G5 non-iSight mobo. It's never been recapped. Either it hasn't been used much or I got lucky.

    G5momo.jpg
     
  10. tigerintank macrumors regular

    Joined:
    Jun 16, 2013
  11. JoyBed thread starter macrumors member

    JoyBed

    Joined:
    Jun 14, 2019
    #11
    Thanks for this photo! I am missing some resistors and two transistors... Now just to kill myself. I can ask for you to measure the the resistors for me but you cant just slap any transistor there. I want to cry.
     
  12. z970mp macrumors 68000

    z970mp

    Joined:
    Jun 2, 2017
    Location:
    A UNIX System
    #12
    We've all had problems like this along the line.

    We've got you... :)
     
  13. Eriamjh1138@DAN macrumors 6502a

    Eriamjh1138@DAN

    Joined:
    Sep 16, 2007
    Location:
    BFE, MI
    #13
    Maybe you can find your values in this list of Apple mobo part numbers. You may have to google the PN for the iMac G5 first.
     

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12 July 23, 2019