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Re-Balled RAM but we still have no boot up

We have a nice 2012 MBA (A1466) (820-3209) that had a 3 beep RAM issue.

We removed the RAM, Cleaned up, No corrosion found, Re-Balled and installed again. Now all we get is an orange / green light on the charger. It appears that all the power rails are intact with no shorts. Q is why isn't it giving us 3 beeps when RAM isn't being detected / failed RAM chip. What are we looking for to check if each RAM chip is functioning or getting power? @oldturkey03 any insight please?

We initially used this video to diagnose.

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5 Comments:

Did you reuse or replace and did you replace the full set with matching chips which are the correct size for this system.

If you upgraded the RAM to larger or lower units you do need to alter the select.

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@danj Same original RAMS Re-Balled and installed. Before it powered up to 3 beeps and now nothing at all.

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Do you have access to a good scope? You'll need to probe the chips RAS & CAS strobes. RAS and CAS in DDR Memory

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@danj Yes, there are some chips next to each RAM that we are going to look at to see if one or more has a failure, hence why I pointed to @oldturkey03 as he is the circuit board master ;)

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@livfe - The direction I was pointing you to was to see if the needed signals where present for the RAM chips.

Think it this way.. I slide my finger along a grid one via a column and the other across a row where they meet is the data cell (0 or 1) here we are looking to see if that part of the circuit is working. If we probe the different rows and columns I think you'll find a few failing as one chip was not properly soldered

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