[SOLVED] Help with Mac pro that starts powering up and thencuts power

[TECCS]

So I have been working on a Macbook pro 2009 A1297

When i got it it would power up light would come on and would start to boot. before the chime it would power back off. If you kept trying it would chime get loading bar and then cut out again. accasionally it would start properly and then would load and stay on.

tests run

• reset PRAM NVRam
• safe mode
• Run Tech tools pro all tests (1 stick faulty RAM Replaced)
• Crystal disk info on HDD SMART Fine
• Diskwarrior
• malwarebytes
• tried powering from just battery no full boot
  
• unpluged battery and left unplugged as turned on (seemed to help last night)
• tried different power adapter

less attempts than yesterday but still issue powering through even with battery unplugged about 3 times pressing the power button.


Any guidance please guys


Thanks

 

[timeshifter]

Is your power adapter the right wattage? They make three different sizes. I've had trouble using a smaller lower wattage power adapter on MacBook Pro laptops before.

 

[Philippe]

Thermal shutdown maybe?

 

[Markverhyden]

SMC reset?

 

[TECCS]

Is your power adapter the right wattage? They make three different sizes. I've had trouble using a smaller lower wattage power adapter on MacBook Pro laptops before.

I am having a new adapter delivered today to double check on that

 

[TECCS]

Thermal shutdown maybe?

I don't think its a thermal shut down as its been improving the more faults i have found and it now powers up more often and stays on after a few startup attempts. i will see if i can get a progrsm to do temp readings from somewhere to check though thanks

 

[TECCS]

SMC reset?

Think I tried this mark but it was befor the other problems were found so i will try again to make sure

 

[TECCS]

Right I have tried a new power adapter not worked. tried a new battery not worked and tried the SMC reset still nothing I'm afraid. Any other Ideas

 

[Markverhyden]

Probably a logic board. Last thing to try since you did not mention if you did yet - Apple Hardware Test

https://support.apple.com/en-us/HT201257

 

[TECCS]

Probably a logic board. Last thing to try since you did not mention if you did yet - Apple Hardware Test

https://support.apple.com/en-us/HT201257

Just tried that and the apple hardware test wont run either freezes on gray screen or boots into OSX

 

[Greg Kristy]

Just went through this same mayhem. Try this:
Hit the on button, and then hold down ANY other key on the keyboard. Does it just stay on as long as a key is pressed?
That's the clue. The diagnostic procedure to rule out what definitely was my issue is to pull out the ZIF ribbon cable that leads to the keyboard. Then use the either the power on jumpers or short pin 7(sometimes pin 5) of the systemboard's keyboard connector to ground. In my case i was astounded as before I couldn't get it to stay on for more than 10 seconds. It worked perfectly.

So knowing that the power on button is the culprit, I tried reseating, cleaning, shorting, everything. But it didn't help. The solution was to swap out the keyboard. I suspect that the on/off signal power rail or wire was being distorted with AC interference from something. Thus making the MacBook think that you are constantly pressing the power button over and over again.
In my case, swapping out the system board would not have solved the problem.