Strange power issues

Discussion in 'Mac Pro' started by Bunnychick, Mar 16, 2016.

  1. Bunnychick macrumors newbie

    Bunnychick

    Joined:
    Mar 8, 2016
    Location:
    California
    #1
    Hello everyone. I have a Mac pro 4,1 (early 2009) that I recently upgraded from an 8 core 2.66GHz machine to an 8 core 2.93GHz machine. I have installed a Diamond Multimedia AMD Radeon HD 7870 graphics card from my old Windows PC and also installed 32gigs of DDR3 ECC Registered ram that I picked up on eBay.

    Recently I have noticed that right after installing or changing a component, pressing the power button only causes a click sound but nothing happens. If I pull the power cable and wait a second before plugging it back in, the Mac powers on just fine. Then 2 nights ago when my ram arrived and I installed it I started to have more problems turning it on. Eventually after unplugging the power and connecting it again I can get it to power on but sometimes I need to try a few times. The following are things I have also noticed but I do not know if it's normal or not.

    1. When connecting the power cable a red light flashes once from behind the front grill of the case.
    2. When powering it on, a red LED located directly behind the rear most CPU flashes once while powering on but does not remain lit and the machine boots up fine.

    I have tried putting the original ATI 4870 card in the machine but the symptoms don't change. On a side note, before installing the upgraded ram the machine would randomly reboot if I am in Windows 10 via bootcamp and I would get a strange error about a hardware issue and relating to memory. I no longer have that ram in the machine after upgrading and have not had a chance to boot into Windows yet to test but I thought I would toss in this info.

    The only thing I can think of is that maybe the machine does not like all the hardware changes and it may need a reset. I see that there is a small white button on the main logic board directly adjacent the SMC battery but do not know what that is for.

    Does anyone have any ideas what I can check? I have invested money into this machine I inherited and would like to find a solution.

    Thank you

    Bunny ^_^
     
  2. ApfelKuchen macrumors 68030

    Joined:
    Aug 28, 2012
    Location:
    Between the coasts
    #2
    First off, it's not a good idea to install new components while plugged into the wall. Always unplug, for two reasons. First is safety.

    Second, Macs have something called a System Management Controller (SMC), which controls the startup of your Mac prior to OS X booting. It stores certain system parameters in nonvolatile memory. After you've changed your hardware configuration, those system parameters may need to be updated.

    For desktop Macs (Mac Pros, iMacs, and Minis), the SMC parameters are reset by disconnecting the power from the wall, waiting 15 seconds, then reconnecting and powering-up. Nice design on Apple's part - if you disconnect power (as you should) when changing components, the parameters will be reset when you power up. https://support.apple.com/HT201295
     
  3. Bunnychick thread starter macrumors newbie

    Bunnychick

    Joined:
    Mar 8, 2016
    Location:
    California
    #3
    Hi,

    Sorry I should have mentioned but I did unplug it. I have never removed or installed any components with the power connected. That's a golden rule I have followed always.

    B
     
  4. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #4
    It would not hurt to PRAM your Mac after performing each hardware upgrade . This might provide stability to your System .

    Are you powering up your Radeon with two 6 pin power booster cables to the logicboard ?

    Did you clean your PSU with a compressor ? Some cMPs might work fine at idle , but shut down when placed under load because there is dust between the two contact plates in the PSU . The dust prevents the proper amount of juice to be provided to your Mac when it is under load .

    Red light(s) flash at start up within the cMP . That's not worrisome . What is worrisome is when they stay on . Some third party components might normally have status lights on constantly .
     
  5. Bunnychick thread starter macrumors newbie

    Bunnychick

    Joined:
    Mar 8, 2016
    Location:
    California
    #5
    Thank you, I will try resetting the PRAM when I get home. If the problem persists I may take out the PS on the weekend and see about cleaning it.
     
  6. Bunnychick thread starter macrumors newbie

    Bunnychick

    Joined:
    Mar 8, 2016
    Location:
    California
    #6
    Ok so I came home and did the following to make sure that all connections where good.
    First I removed the graphics card, drives, cpu tray followed by the ram. I cleaned out the ram slots with air and reinserted them. While I was at it I did a very untechnological thing and tested the pram battery with the ole tongue test HA HA HA. I know but heck, I have no idea where my volt meter is right now. Anyways I barely felt anything so I replaced the battery with a new one (yes this one stung my tongue LOL)

    Anyways, I put everything back together and plugged in the power. The first time I pressed the button everything came on (unexpected). It seemed to do the fans test on the graphics card twice (never heard that before). After that it booted up without any issues. I shut it down and turned it back on and again, first press did the trick. I have a feeling it was the pram and SMC resets as you suggested but I wanted to play it safe by also checking the components and making sure they where seated right.

    I may buy a can of compressed air and still clean out the PS this weekend since it could not hurt but I am happy now.

    Thank you everyone!!!


    Bunny ^_^
     
  7. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #7
    Glad to hear things are looking up . :) Batteries in Apple Professional Desktop Computers typically last a very long time .
     
  8. scott.n macrumors 6502

    Joined:
    Dec 17, 2010
    #8
    When removing the PSU, be sure to use a properly-sized 2.5 mm hex key. The bolts are pretty soft. I'm wrestling with a stripped one at the moment.
     
  9. Machines macrumors 6502

    Machines

    Joined:
    Jan 23, 2015
    Location:
    Fox River Valley , Illinois
    #9
    I use a Wera 2.5mm stainless L shaped hex driver , for removing cMP PSU and Processor board cage screws . One end is ball headed . P3174536.JPG
     
  10. Bunnychick thread starter macrumors newbie

    Bunnychick

    Joined:
    Mar 8, 2016
    Location:
    California
    #10
    I just used my trusty iFixit tool kit LOL.

    Anyways, unfortunately I took the PS out and apart, checked everything and nothing jumps out as obviously bad. No caps bulging, burnt traces, etc... What I did hear is that I may have dried solder connections so I got out my soldering iron hoping to simply re-melt the connections that look like they may need it. Unfortunately Apple uses lead-free solder and my 30 watt iron just is not hot enough.....

    I am afraid I am just going to have to buy a new PS :(

    For the past week I now need to hold the power button down about 15 seconds, let go and press it quickly to get the machine on. Once on, as long as I do not allow it to sleep, I am fine. It's just a pain to power it on daily :(
     

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