[SOLVED]820-2330 no green light

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Fizzl92

New member
Hello,
i got another problem with an 820-2330. The board has no green light. I cant measure any Voltages i want. Nothing at DCIN Fuse, no PP3V42, no SMC_BC_ACOK or PPDCIN_S5_CHGR. So i don´t know what to check next. Could it be the SMC?
I noticed, that after i plugged my charger in i need to completely unplug it from the wall and wait few seconds until the charger will work again with a good board. If i once plug it into this it´s like a dead charger. But at other Boards it works perfectly fine - no unplug from wall needed.
I measured Adapter_Sense witch jumps between +0,000V and -0,000V. At the moment i plug the charger in (only if i unplug it from the wall before, of course) i can measure at pin 1 & 2 of J6900 a spike of 0,384V for a second. Thats the only sign of life from this board. No evidence of water, soldering etc.
Thanks for any help!
 

dukefawks

Administrator
Looks like a short on the DCIN bus that is why your charger is tripping. Find the short and inject some voltage to see what heats up. I assume you swapped the magsafe board already.
 

Fizzl92

New member
No Voltage anywhere at this board. Yes i tried different DCIN boards but no success (and this DCIN board works with other boards just fine too). Q7065 has 0,000V to ground at pin 1-3. Pin 4-8 are not shorted. Is that normal with no charger plugged in? As far as i can tell the only natural Part to ground from there are Q7030 and Q7035 but these should be closed with no voltage on the gate as they are n-channel (so no way to ground here) or did i miss something? Could that be the short causing this problem?.
 

Fizzl92

New member
On L7030 Pin 1 & 2 0,38V and Pin 3 OL, so no short there. Q7035 has a short (on Pin 5 0,379V), but Q7030 has 0,001V to GND. So the short has to be between Q7030 and Q7065.
 

Fizzl92

New member
I checked them and one was blown. I replaced it and the charger stopped tripping, but still no green light. I followed this path and my guess is that u7000 is bad too. I ordered some ISL6258 because i only have ISL6259 in stock. Maybe that will do it. I hope that i can do the rest alone. If i get stuck i´ll let you know. Thank you so far!
 

Fizzl92

New member
Not without measuring. I came to this conclusion but i´m not sure if its right. So, after i exchanged C7030 the short was gone and the charger was no longer tripping, but still no green light. I can hear a silent clicking sound coming permanent from the board and sometimes the green light appears for a second if i plug it in. This sound i heard not the first time and often it was a bad transistor pair of the buck converter (from my experience), so i exchanged Q7030 and Q7035 too, but still no green light.I checked PPBUS_G3H and it was not there. Voltage came in pin 5 of Q7030 but not out of pin 1-3 because on pin 4 was 0V. CHGR_UGATE is not there which comes from U7000. Also CHGR_ACOK is not there and not shorted (so no green light). I measured around and R7001 is shorted on both sides too, so U7000 is not told to turn on. Also R7010 has Voltage at pin 1 but a short at pin 2 and R7002 is shorted on both pins too (but it should only be connected to GND on pin 2). These 3 resistors are all good, so my conclusion was that the only path to ground here is U7000 (or at least 3 caps around it must he shorted). So i ordered a new U7000. I hope my troubleshooting process is not completely garbage. I just don´t want to steal your time for every step that i maybe can solve myself.
 

Fizzl92

New member
My ordered ISL6258 arrived and i soldered it in. Now there is no short on R7001 anymore, but still no green light. So i need to ask you again for help. Is it normal that on R7001 i measure 0V on both sides? Now CHGR_ACIN is around 3,9V but SMC_BC_ACOK is not there. I noticed, that CHGR_DCIN is around 1V but jumping up and down a little. Is that normal? On Pin 2 of D7005 is 16.6V dipping down to 16.2V. Resistance to GND on SMC_BC_ACOK is with charger plugged in around 0,03V but after i unplug the charger it slowly goes up to 0,505V. So i´m really confused again...
 

2informaticos

Administrator
Staff member
"Resistance to GND on SMC_BC_ACOK is with charger plugged in around 0,03V"
WOW!!!
I think somewhere in the forum presentation I've read something about this kind of measurment.
If continue like this you may burn something more...
BTW, write 030, or 505 when you use diode scale; this way is better to understand.
"CHGR_DCIN is around 1V"
So D7005 is burnt too; U7000 killed it...
 

Fizzl92

New member
Thanks for the replys! First of all sorry for the long time i need to answer. I´m not able to work as often on this as i like to. I wanted to do measurements yesterday but i couldn´t - so i can get back to this on monday i hope. But i already did a little research and have a question. Can the problem with CHGR_ACOK occur because U7000 is not powered right? (CHGR_DCIN not there). And is there an equivalent part to D7005 on some other board? I have not the exact same Diode and can´t find a matching one.
 

Fizzl92

New member
I replaced D7005 wit another diode with equal size. Now SMC_BC_ACOK is there but jumping between 1,8V and 3,3V. Diode Mode reading is 1,115V. PP3V42 is ok. Is this indicating a problem with the SMC?
 

Fizzl92

New member
PPBUS is only 0,6V. I can not find any R7005 in schematic or boardviev. Did you mean R7001? Voltage there is 5,09V on both pins. CHGR_ACIN is jumping fron 3,2V to 3,9V. CHGR_DCIN is too. I learned from Louis videos that this can be related to current sensing. So i checked R7020 (it was fine ~2 Ohm) and R7021 and R7022. R7022 was 20 MOhm and R7021 was 1,8 KOhm. I replaced both and PPBUS is now back 12.6V. So CHGR_ACIN and CHGR_DCIN are now also steady 3,9V / 16.3V. Also SMC_BC_ACOK is there. Its 3,27V. PP3V42 is also 3,41V. But still no green light.
 

dukefawks

Administrator
OK then the ISL circuit seems working now. Have you tried a known good magsafe board? What is voltage on pin 5 of U6915?
 
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