820-3115 starts from full battery 1/4 spin from empty or no battery.

rany

New member
Hi there Louis, Duke, and everyone else helping out. Thank you for this great resource.
I have an 820-3115 giving me a headache. Probably current spike killed it.
Among others, L6995 was damaged, ISL and SMC were both shorted to ground. Many resistors were off (reading incorrectly).
After replacing all the above and then some more (this was my most complex attempt yet and some other components may have been replaced without need).
Now will start and charge from battery that is holding a charge, but will charge extremely slow. Won't start and charge a dead battery. Will quarter spin without a battery.
I can't think of anything more to look for.
What rails or lines should I check and report about?
TIA!
EDIT: I remembered two important incidents. When I thought I fixed everything at the beginning, except ISL because I did not yet have them in stock, I borrowed one from a laptop that came in for a different issue and my laptop seemed to function properly, except I don't remember using a flat or full battery. It booted to a flashing folder. So I put the ISL back and waited for Louis to send me the ISLs I ordered from his website.
Then I was able to get a known good donor board. Harvested the ISL and installed it. Plugged the MagSafe improperly aligned (saw a spark) and probably (??) fried the one wire circuit. Started replacing a bad resistor and caused a spark THEN noticed that I had foolishly left the MagSafe attached as I was mad at my 1st mistake. Later after that replaced all the bad resistors I could find as well as the ISL with a new one, and ended up with the problem described above in the title. Not knowing if I caused more damage or this was never solved to begin with.
 
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leonattpcs

New member
I know this doesn't add anything constructive, but that sounds like the u2/usb ic issue in certain iPhones and iPads.
 

Crizz

Member
This is another case where the improperly aligned MagSafe kills the OneWire circuit

I cant remember any Video of Louis pointing out how important the alignment of the adapter is...
It is more likely the opposite way how he handles the MagSafe in his videos when he tests boards!
It looks like he connects the cable by throwing it on and disconnected it by knocking it off with the thumb with absolutely no care!

LOUIS! Make a video "How important is the alignment of the MagSafe adapter" :)
 

larossmann

Administrator
Staff member
This is another case where the improperly aligned MagSafe kills the OneWire circuit

I cant remember any Video of Louis pointing out how important the alignment of the adapter is...
It is more likely the opposite way how he handles the MagSafe in his videos when he tests boards!
It looks like he connects the cable by throwing it on and disconnected it by knocking it off with the thumb with absolutely no care!

LOUIS! Make a video "How important is the alignment of the MagSafe adapter" :)

It is important, you just have to know how to connect it quickly so it aligns. Sending 18v to the onewire pin takes a lot of effort.
 

rany

New member
Checked them resistors already and they read correctly...
Check the traces for continuity? This is not a water damaged board, although current sensing resistors were very badly burnt when it came in. Could the traces be partially damaged?
 
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rany

New member
Checked the resistors already and they read correctly...
Check the traces for continuity? This is not a water damaged board, although current sensing resistors were very badly burnt when it came in. Could the traces be partially damaged?
 

larossmann

Administrator
Staff member
measure pins 27/28 and 17/18 in resistance mode on the meter. it will check all traces and all resistors in one measurement, the total resistance shouldn't exceed the total combined value of all resistors in the circuit.
 

rany

New member
OK will re-check that on Tuesday and report with findings. We're away on (rare) Easter Holiday till then. Thanks.
 

mnaty

New member
Louis can we get a video request forum section just for request, with some form of voting so that you have a measure to weight importance of video priority. Thos will also help connect youtube videos to membership, so that it hopefully bolsters member sign ups... Which fuels keeping this forum current and lively.
 

rany

New member
OK back to this project. It had moved to the bottom of the pile, now back at it again.
I checked resistance and R7051 was > 150Ohm. Now my tech who was working on this told me that he replaced current sense resistors before and they would soon fail. It could be true because I don't think he'd miss R7051 being that off.
I replaced it, and also touched up the pins on the ISL because pins 15-20 seemed a bit off, missing solder.
Plugged it in with the flat battery that came with it, and I get green then amber light using 85W adapter. But the more I add components, the less time the fans and laptop stay on.
27/28 now 20.5 Ohm.
17/18 now 3.1 Ohm.
With everything plugged in => quarter spins and reboots.
With HDD and DVD disconnected => chimes, screen lights, then turns off and reboots.
I am guessing "something" is not putting out enough power. I am hunting for this now, although I have no experience with this part of the circuit yet.
Hope someone can point me in the right direction, seeing that I've had this board for so long and would love to hand it back before it celebrates it's anniversary at my workshop.
 
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rany

New member
It is important, you just have to know how to connect it quickly so it aligns. Sending 18v to the onewire pin takes a lot of effort.
Louis, can I use a MagSafe 2 board for a MagSafe 1 computer? I can then add to it a MagSafe 1 to MagSafe 2 adapter which will align the pins correctly for me... What do you think? Overthinking it? Or fool-proofing it?
 

larossmann

Administrator
Staff member
I have never tried that. I have used a magsafe 1 charger to turn on a magsafe 2 computer, but I doubt this is the recommended practice.
 

rany

New member
measure pins 27/28 and 17/18 in resistance mode on the meter. it will check all traces and all resistors in one measurement, the total resistance shouldn't exceed the total combined value of all resistors in the circuit.
As posted above, now current sense resistors are OK.
So I checked (I figured that I should look for PPBUS_G3H):
L7030: 12.6V in, 12.58V.
F7040: 12.58V in and out.
Isn't 12.58V enough? Now using an original 60W adapter, without anything connected fan spins to full speed and stays ON all the time.
 

rany

New member
I asked about using a MagSafe 2 board, with "MagSafe 1 to MagSafe 2 adapter" sold by Apple. Since this adapter has the edges, you can't mis-align the charger head and short anything.
 

rany

New member
That voltage is ok, anything on DisplayPort, do not plug internal screen, only displayport.......
:( too late?! Went back to try this, plugged it in before connecting the MiniDisplay Port, and it would only quarter spin.
Green light on charger. Tested again current sense resistors, they are OK. L6995 has 3.47V. Pin 2 of U7000 has 16.55V. F7040 has 12.58V. But only very slight quarter fan spin and nothing on Mini Display Port of course because the board isn't starting anymore. It's been doing like this all week. We find and fix a bunch of things, and it runs for a short while, suddenly it quits!
 
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