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Binary_Kramer 05-08-2013 12:24 PM

Where to test MBP Logic Board?
 
2 Attachment(s)
Hello, this is my first post and I know that many are probably tired of hearing this question posted, however I couldn't work the search properly or just didn't come up with the answer I needed. The have a Logic Board from a Mac Book Pro 13 it is a 2011 model I believe. Coffee was spilled on it, and it is not powering on or anything.

I have soaked, and cleaned the board in denatured alcohol, and removed the corrosion with a toothbrush, and it is now dry.

My question is, where do I touch my multimeter testing points on this logic board to find where my troubles are coming from. I am not familiar with using a multimeter so a settings suggestion wouldn't hurt either.


I want to know how I test various points to find a bad capacitor, or other various components.

I have access to the following; hot air rework station a digital multimeter, and I can purchase parts if needed.

Attachment 19042

Attachment 19043

pigoo3 05-08-2013 01:21 PM

Quote:

Originally Posted by Binary_Kramer (Post 1514289)
My question is, where do I touch my multimeter testing points on this logic board to find where my troubles are coming from.

You don't. Modern computer logic boards are wayyy too complex...and the individual circuitry is wayyy too small for this sort of troubleshooting. And even if it could be done...there is absolutely no way you could replace whatever transistor, capacitor, or resister was bad.

Quote:

Originally Posted by Binary_Kramer (Post 1514289)
I am not familiar with using a multimeter so a settings suggestion wouldn't hurt either.

Do you know what this is analogous to?? This is like someone saying that they want to perform brain surgery on someone...but has absolutely no medical training...AND...doesn't even know how to use a scalpel!!!

Like I already mentioned...modern computer logic boards are way too complex to diagnose or repair. Your only real option is to purchase a good working replacement logic board. AND in many cases...replacement logic boards are so expensive that it isn't worth it (you could buy the same working computer for about the same money).

And yes...I have probably answered this very question hundreds of times...and I have given the same answer/advice!;)

- Nick

Binary_Kramer 05-08-2013 01:38 PM

1 Attachment(s)
Quote:

Originally Posted by pigoo3 (Post 1514300)
You don't. Modern computer logic boards are wayyy too complex...and the individual circuitry is wayyy too small for this sort of troubleshooting. And even if it could be done...there is absolutely no way you could replace whatever transistor, capacitor, or resister was bad.

- Nick

Nick, thanks for the reply. One more question. I see pictures from the research I have done. Like the one I attached below, it refers to a G3Hot location? Could you at least tell what this does and how to test it?

If there is no way to test and find a fault location is there at least a way to test the entire board or see if one main item is or is not receiving power?

Attachment 19044

pigoo3 05-08-2013 01:53 PM

Quote:

Originally Posted by Binary_Kramer (Post 1514302)
I see pictures from the research I have done. Like the one I attached below, it refers to a G3Hot location? Could you at least tell what this does and how to test it?

I'm not trying to sound like a "wise-guy"...but did you read the red lettered decription in the photo?...it pretty much says what it does.;) "Shorting-Out" these two spots on the logic board...is a way to start the computer. Someone would do this if they thought they had a bad power button. A "professional" may also do this for various reasons (such as activate the logic board on the repair bench if it were attached to a power source).

Quote:

Originally Posted by Binary_Kramer (Post 1514302)
If there is no way to test and find a fault location is there at least a way to test the entire board or see if one main item is or is not receiving power?

There probably is...but not something you or I could do as amateur compute repair people. Also...there really aren't that many "main items" on the logic board. It's mostly teeny-weeny circuits (transistors, capacitors, resistors)...which are too small to replace (and there's probably no way to find replacement parts).

Everything is VERY small & soldered onto the logic board...and amateur home repair folks cannot make these repairs. I'm not even sure if Apple even repairs busted logic boards. Bad ones that they replace may simply be tossed into the trash. It may be too labor intensive...or even downright impossible to repair a modern logic board.

Believe me...I'm a pretty frugile person...and I do my own repairs on everything. If repairing a computers logic board were possible by a home user...I would most likely know how (or at least if it were possible)...and I would be doing it!:)

- Nick

Raz0rEdge 05-08-2013 02:34 PM

To truly debug at the hardware level (first a multimeter is definitely not enough), you need access to the schematics to be able to trace through the connections to where things are coming and going. You need to figure out where all the power rails are and if they are powering up. You need to go through all the caps, resistors and ensure that they are all working. Finally, you need to go through all of the components and ensure that they are operating properly with some output that can actually be monitored..

None of these things can be done by just looking at the the logicboard. The nature of liquid and electronics is that you never know what part has failed and is causing problems. Sometimes, if you're lucky, you will get a clear indication of a burned out or blown of cap/resistor that can be potentially replaced to get going. However, a lot of components are soldered on by machines and not by hand and if they fail, they may fail without any physical indication and even if you were to determine the failed part, getting the replacement and doing the replacement isn't possible with just a soldering iron..

So believe me when I say that we are not discouraging you from finding the problem that is ailing the logic board, but are just telling you that as a lay person without the necessary Apple-level information it's hard to know where to start..

chscag 05-08-2013 03:06 PM

To add to what you've already been told..... Modern boards such as the logic boards which are used in Macs and other computers have the components surface mounted. In some cases, the board has multi-layer circuitry in order to save space. Only certified Apple Technicians at official repair depots have the proper equipment and software to test these boards. And since everything is proprietary, that information is not released to the general public. As Nick pointed out, its usually best to just buy a new machine rather than try to salvage that one. Not saying it's impossible, but very likely not practical.

techiesteve 05-08-2013 03:30 PM

Quote:

Originally Posted by Binary_Kramer (Post 1514289)
Hello, this is my first post and I know that many are probably tired of hearing this question posted, however I couldn't work the search properly or just didn't come up with the answer I needed. The have a Logic Board from a Mac Book Pro 13 it is a 2011 model I believe. Coffee was spilled on it, and it is not powering on or anything.

The boards S/N indicates it's older than you expected, it's from a MBP 13" mid 2010 2.4 GHz. Liquid damage can and does cause multiple faults. If it hadn't suffered liquid damage it had AppleCare until sometime in June.

There is a very valid reason why Apple doesn't permit component level repair in Apple Stores and by AASP's. For each store to employ skilled staff to operate ATE, and the cost of the ATE and rework stations make it not economically viable. Plus extensive time consuming testing would be required. It is easier to have the boards repaired at central locations and repaired/tested boards available via overnight shipping for fast repairs.

For you and I there is no way to undertake the testing you hoped to undertake, other than test the complete logic board back in the MacBook Pro (presuming the liquid didn't damage the top case with keyboard as well). I once worked in a manufacturers repair facility where we used ATE, and employed programers with the full support from the manufacture. No way would I attempt to repair a complex multi layer board myself.

Your later picture shows a 13" mid 2009 2.26 GHz MBP logic board. Typically the logic board power on contacts would be used in attempting to diagnose a defective power button or if you suspected the keyboard circuitry had a liquid spillage inhibiting power on. Then you would remove the keyboard flex cable, plug in an external mouse and keyboard, then short together the two contacts you identified. If the MBP then powered up OK, it would confirm you needed a replacement top case with keyboard.

Binary_Kramer 05-08-2013 03:41 PM

That was a lot of useful information, thanks a lot for all the responses. I am just going to test the capacitors and other major things with my multimeter, and then attempt a reflow with my hot air gun. After that I will call it quits. Thanks again.

Kramer

pigoo3 05-08-2013 03:56 PM

Quote:

Originally Posted by Binary_Kramer (Post 1514316)
That was a lot of useful information, thanks a lot for all the responses. I am just going to test the capacitors and other major things with my multimeter, and then attempt a reflow with my hot air gun. After that I will call it quits. Thanks again.

You probably have heard of the example of dropping a running hair dryer into a bathtub full of water. Not very good for the hair dryer or someone if they should be in the tub!;)

Kind of the same thing spilling liquid on a laptop computer. Liquid + laptop = dead laptop. I'm talking possibily short circuits, sparks, smoke, etc.

Test all you want...and "reflow" all you want...just to satisfy your curiosities.:) But I think that at the end of the day...chances are you will still have a dead laptop!:(

Two realistic options:

- Buy a used replacement logic board (if the cost makes sense)...which it usually doesn't.
- Use the money that would be used to purchase a replacement logic board (plus probably additional cash)...and get a replacement used MacBook Pro just like what you have, get a new computer from Apple, or get a refurbished computer from Apple.

Good Luck,:)

- Nick


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