Late MacBook Pro - no chime, troubleshooting

[wileybot]

Hello all,

I have a A1260 2.6, that will not boot,
(1) No startup sound
(2) Solid power light (not flashing)
(3) fans spins

Tried
PRAM and SMC/PMU reset didn't work.

Bought a used MB and replaced it same issue as above, seller took the board back but did state it worked when he took it out of another pro.

Then I bought another mb bottom case (used but working per the seller) same model a1260 (but 2.5) this is complete bottom case minus the HD, memory and CD drive. Same issues as above no change, tried all the fixes as well. This leaves me to believe it's not the logic board.

I disconnected HD, topcase (shorted on using pins to start), CD drive, display, same issue as above.

I tried the memory one stick at a time in different slots. When there is no memory I get the error beep.

1. Question can the power charger be bad, even though I get a green light?
2. Also I have a battery that is good, it wont start with that either. It looks to be taking a charge with the power adapter...
   
3. Can a bad display prevent it from booting?
   
4. Can both memory sticks be bad, what are the odds of that?

HD, memory, CD etc all worked up to one day...then it was just off.

Why on earth wont this boot up, is this another bad logic board? I feel that everything has been swapped at one point or another.

Thoughts?



thanks for reading.

 

[GhettoMrBob]

Hello all,

I have a A1260 2.6, that will not boot,
(1) No startup sound
(2) Solid power light (not flashing)
(3) fans spins

Tried
PRAM and SMC/PMU reset didn't work.

Bought a used MB and replaced it same issue as above, seller took the board back but did state it worked when he took it out of another pro.

Then I bought another mb bottom case (used but working per the seller) same model a1260 (but 2.5) this is complete bottom case minus the HD, memory and CD drive. Same issues as above no change, tried all the fixes as well. This leaves me to believe it's not the logic board.

I disconnected HD, topcase (shorted on using pins to start), CD drive, display, same issue as above.

I tried the memory one stick at a time in different slots. When there is no memory I get the error beep.

1. Question can the power charger be bad, even though I get a green light?
2. Also I have a battery that is good, it wont start with that either. It looks to be taking a charge with the power adapter...
   
3. Can a bad display prevent it from booting?
   
4. Can both memory sticks be bad, what are the odds of that?

HD, memory, CD etc all worked up to one day...then it was just off.

Why on earth wont this boot up, is this another bad logic board? I feel that everything has been swapped at one point or another.

Thoughts?



thanks for reading.

I'd be willing to bet it's something with the RAM., especially being that it beeps without any in and doesn't do much when installed. I'm guessing you don't have any laying around or you would've already swapped it in.

One thing you could try is insert each module individually into each slot and see if it'll boot (mem module 1 - slot 1; mem module 1 - slot 2; etc.). That would determine if possibly one of the slots is bad and/or just the module itself is bad.

I've never seen a screen stop a unit from powering on.

 

[wileybot]

memory swap

Thanks GhettoMrBob

I did try the memory swap, stick 1, in slot 1, slot 2 then stick 2 in slot 1, slot2 etc. No joy.

Its very perplexing.

If the mobo, power supplier is good, all thats left is the HD, CD, Top case and display and memory. I disconnect all of that (jump power using the mobo power pad connections), with the above memory and it still doesnt work. I will need to find a good stick of memory out there and see if that the culprit if not....well heck.

 

[DeltaMac]

If you have ruled out the RAM, and the replacement logic board behaves the same, then there's not much left.
You get the sleep LED on (no flashing), and if that stays on steady, most likely the video is not detected properly.
Can you see ANY video image, even if it is dark display (shine a bright light into the screen from different angles, looking for icons/dock/top menu - anything at all
(Have you tried an SMC reset?)
Be sure to try connecting an external display, if possible.

So, if all else fails, it's the Display cable
or
the Display...

 

[wileybot]

bad display stops it from booting?

Thanks DeltaMac, I have tried the SMC reset, sleep light is steady on, remember I get no boot signs, chime or HD sounds of use (after first seconds).

I am guessing that the computer would boot with chime and other signs of life even if the display was bad, I would think its independent of the boot up cycle? Am I wrong on that?

I would be curious to know, I seem to find conflicting information around the display being plugged in and if it will boot. I will see about an external cable for monitor but again, am thinking i am not even getting it to boot let alone display.

-thanks all for your help.

 

[DeltaMac]

When booting, do you get a caps lock key light when you toggle that caps lock?
If so, and you get the steady LED on the front edge, then the computer is not turning on video. (The LED goes out when the video turns on.)
That either means a bad video connection (the cable or its connectors are not seated properly), the LCD panel is bad, or the logic board is bad.
You have replaced your logic board, and still have the same problem. "Maybe" you have eliminated the logic board (because you fully trust the parts seller )
Like I said in my other post, there's not much left. Cable, or display panel.

The external display may, or may not help. If you had an external to try, then I would try it out with the top lid closed, and an external keyboard/mouse, in addition to the display. Power it up, close the lid, attach your external display and keyboard/mouse. Your Macbook would then be sleeping, in clamshell mode. Press a key on the external keyboard to wake it up. In theory, the external display will work, and the internal screen will remain OFF (assuming the lid is closed.) And, that should work, bypassing a possible bad internal screen. If the logic board is bad, then that likely still won't work...

 

[wileybot]

ah-ha cap lights key...new clue?

I am not getting the caps light key or any key lights at all, front light yes. Does this represent a a no boot by the logic board?
I don't necessarily know for sure the logic board/bottom case is good, it is from ebay. I have gone through two that have claimed they are good, coincidence? I cant say for sure.

 

[DeltaMac]

I am not getting the caps light key or any key lights at all, front light yes. Does this represent a a no boot by the logic board?
...

Caps Lock key does not do anything until you press it.
I don't expect that any other keys will light, because you are not booting up, but the caps lock LED should come on whenever you have good power, and should come on when you press it. It definitely should toggle on and off when the front LED is on.

Is your battery OK? (Does it hold a decent charge?)
*Important* Are you using the correct power adapter (should be 85W, not a 60W). If the battery is marginal, or has little charge, then not too much will happen with a 60W adapter, so double-check that you have the 85W.

If you ONLY get the power LED on steady, and the Caps Lock light does not come on when you toggle that key, you will need to open up, and check for good seating on _every_ internal connector you can get at. Don't rely on how they look, physically unplug and reseat all.

 

[triplelucky]

On the unibody’s I’ve worked on the caps lock LED won’t come on until POST has completed. The SIL can be solid on with no Caps lock LED if its stuck somewhere pre POST..

 

[wileybot]

solved!

Turned out DeltaMac's suggestion to try a external display does allow it to boot. The display laptop must be bad, not sure how it will kill a boot sequence, but there you have it! thanks All!