thread top ad

Collapse

Announcement

Collapse

READ BEFORE REGISTERING SO YOUR ACCOUNT WORKS

In order for your account to be activated INSTANTLY, your PayPal email MUST MATCH THE EMAIL YOU USE TO REGISTER YOUR ACCOUNT ON THIS FORUM!! If your PAYPAL email address differs from your FORUM email address, your account will have to be activated MANUALLY when a customer service agent gets around to it.

I realize this sucks, and I do apologize.
See more
See less

820-3115-B Green Light No Power

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    I get a beep when no RAM installed. I'll go back to U7400 and check all the resistors. I swear this board is a rite of passage from the repair gods to test my patience

    Comment


    • #17
      Had a look around U7400 and cant find anything else that looks bad.

      I removed R7550 and get voltage to pin 1 (think it was around 1V) as soon as I replace R7550 I get 0V on Pins 3, 4, and 5 on Q7550 and 0V on PPVCORE_S0_AXG.

      Dead CPU?

      Comment


      • #18
        picture on external monitor if you use thunderbolt to vga adapter?

        Comment


        • #19
          Originally posted by larossmann View Post
          picture on external monitor if you use thunderbolt to vga adapter?
          Nothing. I put back the BIOS chip from my donor board to see what happens and I got no drop in voltage on cpu vcore or signs of trying to POST. it could be a BIOS issue after all as original spill was around that area. Will order in another and pray

          Comment


          • #20
            If it beeps all power is ok and POST runs. It can still hang during POST for 1000 reasons. Probably corroded resistor or crap under PCH/SMC.

            Comment


            • #21
              Cheers have given up on this rabbit hole to hell especially as I don't have decent enough tools at the moment to do any large scale BGA rework but was a good learning experience nonetheless getting the clock signal and CPU voltage back. Thanks again for all your help.

              Comment

              thread bottom ad

              Collapse
              Working...
              X