MBP 820-2879B Board view vs actual board

[Mackayak]

I'm trying to troubleshoot a 'dead' Macbook Pro 2010.
The logic board is 820-2879B
Thanks to everybody who have uploaded schematics and .brd files here - it's a fantastic resource and a great help to me.
However, the .brd file that I've found here seems to be for a different version of the 820-2879 board as the component layout is different in a few areas.

Does anybody have a .brd file for the 820-2879B logic board?
It would be a big help.
Thanks

[piernov]

Re: MBP 820-2879B Board view vs actual board

Is the pictures supposed to show any differences? I don't see any… But I see slight liquid damage.

[stj]

Re: MBP 820-2879B Board view vs actual board

harly "slight", that's a mess!

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

Is the pictures supposed to show any differences? I don't see any… But I see slight liquid damage.

I know there's a lot of dirt - probably from a liquid spill- but I'm trying to figure out the exact cause of the failure.
I doubt that just cleaning the board will solve the problem, but it's on my list of things to do. I need to remove the speaker and heatsink first.

Perhaps these pics will help show some differences:

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

hardly "slight", that's a mess!

Yes, it does look bad when magnified.
I have seen 'bad looking' electronic boards working, and 'good looking' boards that don't work!

What's the best way to clean a board like this?

I don't have an ultrasonic machine.

[Th3_uN1Qu3]

Re: MBP 820-2879B Board view vs actual board

If you don't have an ultrasonic cleaner, the old, trusted, tried and true method is to use Isopropyl alcohol and a toothbrush. My favorite solvent is paint thinner, but if you use that you should do the cleaning outside or near a window, because it stinks big time.

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

Cleaned the board well with distilled water and then 99% isopropyl alcohol and dried it.
It looks a lot better but still doesn't work, so I'm continuing with the troubleshooting.

I'll grab a pic of the clean board later today and post it here, just to show some improvement in 'looks'. It's also a lot easier to measure voltages and resistances when the components are clean, so I should have cleaned it as a first step.

The troubleshooting would be easier with an accurate .brd file, though, so if anybody has one, I'd really appreciate it.....

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

A bit cleaner now....

[piernov]

Re: MBP 820-2879B Board view vs actual board

The boardview file is accurate, I'm not sure what you're looking for…

If you state the problem maybe we can help you.
I see a bit of corrosion around R6905 so there may be an issue on PP3V42_G3H creation, several corroded vias on U3900 but as long as it's not shorted, it'll only cause no Ethernet. Before cleaning there was green stuff around Q7620. The SMC being right in that area, it may have crap under it as well.
Well, that's only for this area, we don't know what the rest of the board looks like, but those can already cause various different issues.

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

Piernov-
Thank you for your comments and suggestions- I really appreciate all the help I can get!
:-)
I don't what is customary here; I was thinking it would be better to start a new thread (discussion) about the actual problem and troubleshooting and diagnosis?

Before I do that - a question about power for troubleshooting. Most of the videos (Louis Rossman, Powerbook medic) seem to focus on the charger (getting PP3V42 and the one-wire circuit working to turn on the charger supply). Isn't it simpler to use the battery as power and just follow the voltages into the circuit?

I have a charged battery and can recharge it in another Macbook Pro.

[Flippers McCoy]

Re: MBP 820-2879B Board view vs actual board

This isn't immediately relevant, but I figured I'd clear this up for future reference
The fact that the boardview shows that there are "components" there does not necessarily mean that there will be components on the board. If the schematics shows something there, it guarantees that there will be solder pads, but not necessarily components. If you see a spot on the board where the boardview says there is a component but there isn't on your board, look up the part # (in this case U5101) in the schematic PDF. When I pulled it up, that circuit is titled EFI Debug ROM, which is not a circuit that would exist on a retail model. Also, an easier way to tell, if a component says "NO STUFF" (like R5102 & R5104), that means, without a doubt, you will only see bare solder pads on a retail board.

In my experience, it's simpler to troubleshoot off the charger, then, when you have all your power rails coming on properly, plug it into a the rest of the computer and see if it charges the battery, then if not, troubleshoot that issue on it's own. What I'd advise is hook up the bare board to the charger and test the power rails starting with S5 rails then to S0 and see how far you get to get an idea of where your issue might be

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

This isn't immediately relevant, but I figured I'd clear this up for future reference
The fact that the boardview shows that there are "components" there does not necessarily mean that there will be components on the board. If the schematics shows something there, it guarantees that there will be solder pads, but not necessarily components. If you see a spot on the board where the boardview says there is a component but there isn't on your board, look up the part # (in this case U5101) in the schematic PDF. When I pulled it up, that circuit is titled EFI Debug ROM, which is not a circuit that would exist on a retail model. Also, an easier way to tell, if a component says "NO STUFF" (like R5102 & R5104), that means, without a doubt, you will only see bare solder pads on a retail board.

In my experience, it's simpler to troubleshoot off the charger, then, when you have all your power rails coming on properly, plug it into a the rest of the computer and see if it charges the battery, then if not, troubleshoot that issue on it's own. What I'd advise is hook up the bare board to the charger and test the power rails starting with S5 rails then to S0 and see how far you get to get an idea of where your issue might be

Thanks for that explanation about the boardview - I'll stop worrying about that.


I'll report back once I have some more ideas about the power rails. Basically most of the points on the board where I look for S5 or G3H power rails (like PP3V42_G3H), I get <1 volt. So I've started working my way 'in' to the board from the adapter in following the 16 volts (approx) - perhaps not the right strategy?

[Th3_uN1Qu3]

Re: MBP 820-2879B Board view vs actual board

Your approach is correct, you need to figure out why you aren't getting PPBUS_G3H starting from the adapter on down. See if PP3V42 is there first.

[Mackayak]

Re: MBP 820-2879B Board view vs actual board

Thanks!
I'm just getting organized here with some appropriate tools for SMD work.
Once I get a couple of other (non-electronic) projects out of the way, I'll be back.
:-)