Re: Macbook Pro 2017 15" 820 - 00138 - A Not powering on, Voltages pulsing, 30mA to 2
Use procedure described here to check your pwr signals. It's for 820-00165, which is mostly the same as your 00138, chip references etc.
[URL="https://www.it-tech.com.au/mac-q-a/cpu-vcore-power-rail-and-ppvcc_s0_cpu-voltage/"]https://www.it-tech.com.au/mac-q-a/cpu-vcore-power-rail-and-ppvcc_s0_cpu-voltage/[/URL]Re: Macbook Pro 2017 15" 820 - 00138 - A Not powering on, Voltages pulsing, 30mA to 2
Use procedure described here to check your pwr signals.
kurland
Member
Last Activity: 10-23-2023, 03:12 PM
Joined: 09-05-2020
Location: Kurland
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Re: MacBook Pro 2017 A1706 820-00923 no power, low voltage PPBUS_G3H
I don't see how Q7030/40 could have anything to do with it, your problem is 0 ohm on PP3V3_S5, which goes directly to CPU and loads of other places.
When you removed U8200, is resistance to ground still 0ohm? If so it's likely the CPU if that is getting hot (although that doesn't explain why U8200 got hot)
If you have an infrared camera you would see a short within the CPU starting as a concentrated spot, whereas a more uniform spread of heat is normal. You may also use Zippo lighter fuel like...Last edited by kurland; 10-25-2022, 04:43 PM.Leave a comment:
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Re: MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok
Looks like the battery was the problem. I got the new battery today and it's charging nicely at 3+ amps. Thanks for your help, I learned alot.
Now I just need to get the old one out safely, think I will try the waxed thread method that Paul Daniels did in a video.
Cheers!
...Leave a comment:
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Re: MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok
Thx, will try the System Info thing if I get the login
Mosfets readings:
Source & Drain : 230k
Source Gate : 390k
Gate & Drain : 452k
And btw, the cell beneath the t-pad cable looks more Apple-like, perhaps it's autentic after all
...Last edited by kurland; 10-25-2022, 02:08 AM.Leave a comment:
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Re: MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok
I will need to get the password from the owner for that, will try tomorrow.
The battery is labeled as shown below. Not sure why both 13.05 and 11.40 Vdc is listed.
When I measure the cell voltages directly on the battery board (not the connector, as that is controlled by fets), it says 11.3 volt, so I believe the cells are ok at least.
I don't have tools for that. However, the machine almost looks like new so...Leave a comment:
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Re: MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok
Finally some progress.
The machine now starts normally after cleaning some liquid damage I noticed on the keyboard connector
However, it still doesn't charge the battery.
[LIST][*]PPBUS_G3H stays rock solid at 12.456v, and passed on to Source of P-channel Q7065 via sense resistor[*]ISL9239 tries to start charging by pulling down Gate of Q7065 to pass the voltage to Draing, thus to the battery connector[*]The Drain/battery voltage output of Q7064 goes...Leave a comment:
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Re: MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok
Hi,
The current sense resistor R7060 and the mosfet Q7065 looks ok. The resistor is 0.005 ohm, which I have no way of veryfying. But it measures as a short on my DMM so it's probably ok. Also, the mosfet passes on 12.6v to the battery connector after a few seconds, as expected.
Following up on your comment about the connector I took out the battery board and flipped it (kind of hard because of the cables to the battery). And indeed I found some corrotion...Leave a comment:
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Re: MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok
That's a great tip, thank you.
I scoped the SCL and SDA lines and they look perfectly fine. The SMC is obviously trying to speak to the battery.
I did these measurements with the battery disconnected as I had to take the board out to get to the test points.
SCL line with clock bursts
SDA line with data
Should I try to do the measurements while battery is connected? I mean to determine if the battery answers? I...Leave a comment:
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MacBook A1707 - low batt sign displayed then shutdown - but battery voltage is ok!?
Hi fellow repair gurus,
Liquid damaged A1707 was stuck on 5V. I replaced corroded CD3215 and SMC now successfully raises voltage to 20v.
The fans spin, the screen comes on and displays a "low battery" sign before the machine shuts down.
After that the screen and fan stays off but PPBUS_G3H continue to toggle every 4-5 secs between
[LIST][*]11.4v (and 170mA current draw on usb-c power meter)[*]12.6v (zero current draw)[/LIST]
The toggeling occurs when battery is connected but regardless if external usb-c is connected... -
Re: Strange liquid on damaged GTX1080 card
Unfortunately the board was not fixable. The PCB was completely carbonized half way through. Even after carving out a whole I was not able to get rid of the short. I checked all fets and caps remaining on board and they're ok, so I suspecte it's the GPU itself.Leave a comment:
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Re: Strange liquid on damaged GTX1080 card
Answering myself here,
It seems such oil sweating from thermal pads is common but should not cause a problem.
[url]https://www.overclock.net/threads/video-card-motherboard-thermal-pads-sweating-oil.1496615/[/url]Re: Strange liquid on damaged GTX108...il.1496615/[/uLeave a comment:
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Re: Strange liquid on damaged GTX1080 card
Thanks for feedback, it makes sens from what I see.
But could this really cause short circuits?Last edited by kurland; 11-18-2020, 04:26 AM.Leave a comment:
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Strange liquid on damaged GTX1080 card
Hi,
I'm fixing a GPU card for a streamer, was sent to me by mail. A shorted cap on a power rail has severely burned the PCB.
As you can see from the darkened PCB around the mosfets there are signs of liquid damage. But it's odd because the person says no water has entered the PC cabinet. If you spill something on a desktop you would know I guess...
Funny thing is that the liquid is not only on the PCB but on top of many chips which are tightly covered by thermal padding under the heatsink, even on top of some of the RAM chips
...Last edited by kurland; 11-17-2020, 07:16 PM. -
Re: Microoven POOF after heating up metal kettle, repair attempt
By "heating element", do you mean the cylinder tip in the photo? I haven't testet that specifically. I did however measure the contact leads into the magnetron, and those have infinite resistance to chassis ground. Will test further tonight.
Thanks for your suggestion.Leave a comment:
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Re: Microoven POOF after heating up metal kettle, repair attempt
Hmm, frustrating, cannot find any problems...
Zener diodes are ok, both 10V
HV diodes seems ok, both have Vf ~7 volt
Magnetron looks fine, no visual damage
...Leave a comment:
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Re: Microoven POOF after heating up metal kettle, repair attempt
haha oops .... IGBTs .....
Leave a comment:
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Re: Microoven POOF after heating up metal kettle, repair attempt
> The magnetron was the likely cause of the FIRST problem, the inverter blew again (with mag disconnected) because of other defective parts.
Ok thanks, will check magnetron
> The zener diodes are not the HV diodes.
Of course, I know that.
> You can NOT check the HV diodes, the need to be replaced.
So verifying their forwards voltage does not mean anything?
> The two small zener diodes can not be checked with a meter, they will also check...Leave a comment:
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Re: Microoven POOF after heating up metal kettle, repair attempt
just saw you edited your post. Thanks for additional info, greatly appreciated!!
R713 is populated and measures ok. I will dissassemble magnetron as well and look for arcs.
TBCLeave a comment:
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Re: Microoven POOF after heating up metal kettle, repair attempt
Regarding D710, I found it on the board, but it's not populated, and no sign of it in the schematic.
Do you know this board from before R_J ?
...Leave a comment:
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Re: Microoven POOF after heating up metal kettle, repair attempt
Also, it's not the magnetron, because as I said the thing blew again after replacing components, while magnetro was disconnectedLeave a comment:
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