blue led flashing.
Good morning everyone, I have a Samsung NP750XDA from a very dear friend of mine, unfortunately the display was damaged and he tried to replace it, result: dead notebook!
It seems to start but the blue status led flashes intermittently, the battery charges regularly. When pressing the power button the fan turns on for a moment, the keyboard backlight turns on for a moment, but then it shows no sign of life,
Unfortunately I have not found any diagrams to make measurements, aesthetically the pcb seems perfect, carefully inspected and checked under the microscope...
sdogs
Senior Member
Last Activity: Today, 06:56 PM
Joined: 02-03-2016
Location: Lucca
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Macbook Air A1466 820-00165 no ssd
Hi everyone ;-)
I have a MacBook Air A1466 that doesn't detect the SSD. I tried different hard disks but unfortunately the result did not change, at startup you see the apple logo for an instant and then move on, after about a second, to the flashing folder with a question mark.
I took measurements at U3740 and the following measurements were made:
R3741 pin1 3.3v pin2 1v;
the other voltages seem regular, I measured in diode mode and there don't seem to be any strange values, I noticed something strange, that is, without the SSD connected I have 3.3V at pin 8 (SSD_CLKREQ_L),... -
Thanks Mon2, your help is always precious ;-)
Yesterday I tried a new, non-original but good quality battery and the MacBook works!!!
The problem related to the sensors seemed strange to me, when they entrusted it to me it only worked on battery power.
In summary, I replaced both U3200 and D3302 and the logic was resurrected!!! -
Thank you so much for your help, you help me understand and I am very grateful ;-)
Am I referring to this part of the diagram?
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"Schema I2c scl e sda.png","data-attachmentid":3213158}[/ATTACH]...Leave a comment:
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unfortunately the SMC reset did not give the results I was hoping for, today I should receive a new battery to test, I hope it works.
The only thing that I didn't understand well and would like to understand, the SYS_DETECT_L signal should be the communication between battery and logic, is this correct?Leave a comment:
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when I received the macbook it didn't charge but it worked normally only with the remaining battery charge. I waited for the components to arrive which I then replaced and now it has this problem. If the sensors had been faulty he would have had the same problem, could it be the battery that stopped working?Leave a comment:
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Macbook Air 2020 A2179 820-01958 battery problem?
Hi everyone,
I have a MacBook Air A2179 in my hands that had power problems (5V to the USB-C port intermittently).
After a first inspection I could see that the D3302 protection IC was burnt out, so I replaced it but the problem was not solved, it seems like intermittent 5v input.
I then replaced the two u3200s (CD3217B12ACE) and now I have stable 20 volts and the macbook has turned back on.
Unfortunately I have a further problem, it works very slowly and the fan runs at maximum and if I disconnect the charger it turns off, it's as if the battery was disconnected.
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Today I finally had some time to dedicate to the Mac mini, I replaced the LAN network chip and a small inductance, which was probably shorted, and it works!!!!!
Probably the lack of the BCM577762 chip prevented it from booting properlyLeave a comment:
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in fact it seems like the same circuitry, now I have disconnected the IC and the short circuit is no longer present but there is another problem. Although the Mac mini goes into DFU it returns errors during the activation process, which is not completed.
Could it be the lack of this chip that is creating this problem?
It seems strange to me, it's linked to the LAN network, it shouldn't affect the restore.Leave a comment:
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Mac Mini M1 A2348 component identification 820-02091
Hi everyone ;-)
I have a Mac mini M1 in my hands that I would like to keep for myself, I bought it on eBay at a good price. The Mac Mini boots up, emits the initial dong, and immediately dies.
I saw that unfortunately the schematics and brd are not available so I tried to identify the area that is perhaps shorted, it heats up a lot in that part of the logic.
Using isopropyl alcohol it seems that the component indicated in the photo heats up, actually with measurement in diode mode it is shorted on both pins but the problem, in addition to being positioned in a place that is difficult... -
Re: Macbook Pro 15 A2141 820-01700-A stuck at 5V
I made the measurements you indicated and I put the results, it seems to me a situation similar to other posts of similar problems of this logic board series..... I hope I have some hope ;-)
In relation to the small overheating of u6960, when I injected 1.5v, do you think it is appropriate to remove it to see if the short circuit goes away?...Leave a comment:
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Re: Macbook Pro 15 A2141 820-01700-A stuck at 5V
I found a U9080 isl on a donor a1989 logic board and tried to change it, unfortunately everything remained as before. I'm not sure if the ic I took from the other logic board is working but it's an attempt I made.Leave a comment:
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Re: Macbook Pro 15 A2141 820-01700-A stuck at 5V
the voltage to ground @ F7000, pin #1 = ISL side = 12,21v
the resistance to ground on F7000, pin #2 100 ohmLeave a comment:
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Macbook Pro 15 A2141 820-01700-A stuck at 5V
Happy Sunday everyone,
I have this Macbook Pro 15 A2141 820-01700-A stuck at 5V, it doesn't have any liquid marks or burn marks, I have carefully inspected the logic with the microscope and have not found any anomalies.
By connecting the usb-c tester I could see that it is blocked at 5v, and as a first measurement I checked PPBUS_G3H which has a voltage value of 0.8v and measured in 0.06 ohm diode mode.
I read a bit in the forum and I tried to inject 1v on the F7000 not having any current absorption, I then went up to 1.5v and I had a light current absorption (0.10Amp) and... -
Re: Macbook A1502 820-3476-a no backlight
he assured me that it's his display .... at this point I'm still and I don't know whether to give up .... what do you think?...Leave a comment:
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Re: Macbook A1502 820-3476-a no backlight
Tomorrow I'll ask the owner but I'm sure it's his display, I'll update you as soon as I have the exact information
thanks for your time ;-)...Leave a comment:
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Re: Macbook A1502 820-3476-a no backlight
forgive me if I bother you even on the weekend.. what do you think? it seems that when it detects the display it all goes down the drain
unfortunately I don't have other displays to try, only a 2015 but it's not good for this logic board...Leave a comment:
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Re: Macbook A1502 820-3476-a no backlight
without display connected in diode mode to pin 6 SMBUS_SMC_0_S0_SCL I have a normal value, about 0.64 ohm and 3.3v, also the resistance value corresponds to 2 kohm, so the connected display certainly creates some problemsLeave a comment:
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Re: Macbook A1502 820-3476-a no backlight
pin 3 I2C_BKLT_SCL 5.1v (for about 2 seconds 4.8v then back to stable 5.1v)
pin 4 I2C_BKLT_SDA 5.1v
pin 6 SMBUS_SMC_0_S0_SCL 0v (at pin 1 of the r5351 I have 3.3v, in diode mode at pin 2 I give a very low value practically 0 ohm)
pin 7 SMBUS_SMC_0_S0_SDA 0.4vLeave a comment:
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Re: Macbook A1502 820-3476-a no backlight
what do you think of the measurements? do you think it makes sense to replace the LVDS connector?...Leave a comment:
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