this machine came to me as DOA and immediately found the issue as a 12v short to ground. Is it okay to inject voltage into that rail or does it have a potential path to the cpu or something?
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Flux and remove fuse @ F5200. Then power up again and measure the voltage to ground on pcb pad # 1 on the removed fuse @ F5200. Is the voltage present and stable? What is the voltage?
Then remove all power. Meter in resistance mode. Measure the resistance to ground on pcb pad # 2 on the removed fuse @ F5200. -
12.38v is stable on #1. direct short to ground on #2. 0.3 ohmsComment
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Inject 1 volt (not higher) onto the pin #2 side and test who heats up. If it is a capacitor, it will crumble / crack under the pressure. The fault may be the CPU but TBD.Comment
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was a bad capComment
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Board booting ?
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it boots
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hello everyone , working zebronics power suply 450 watts , 5v ,3.3v givin short to ground black wire, also in circuit at output, resistor was charred but shows right values , after removing resistors 39ohms, 51 ohms, there was no short , no continuity beeps with ground , but after replacing new resistors (now i am not switching it on) ,again short still exists . when i put bigger ohm resistor like 100k ohm , no short beeping sound comes , lower ohm resistor gives continuity beeps ,other big ones donest , as its a working psu , i am confused what to remove now or how to go further now .
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Hello, I have a pcb from an e scooter which had a faulty diode but even after removing it from circuit, it still has a short to ground on the three components circled. I have removed every cap on the board and tested one by one and the short is still there and all the caps test ok. Could this be because I haven’t put a diode back on it yet or where do I go next please? -
Hello everyone,
Firstly sorry for my english, french guy inside.
I brought a macbook pro A1708 - 820-00840 logic board, wasn't powering on.
History is a day, nothing happened when opening the laptop.
Nothing special inside, no corrosion, no liquid damage, never opened.
First, with the logicboard alone on the desk, mesures are :
5v017 and 0.000 amp. nothing else.
Finding a short on the PP3V3_G3H_VR, but not on the PP3V3_G3H (0.540 on diode mode), PPDCIN_G3H_CHGR_R present (5,1 volts) PPVIN_G3H_P3V3G3H around 4.1 volts. PM_EN_P3V3_G3H... -
Greetings to the entire forum, I ask you for help because I'm going crazy. A dear friend of mine gave me a macbook pro M1 A2338 that only works with an external screen. With the internal one, no backlight or image. Only the external display is detected from the system settings.
First I changed the display flat, then I made a backup with time machine and tried a reset in dfu but nothing to do, always the same problem.
I analyzed the logic board, it shows no sign of liquid or visible damage. I then moved on to examine the logic with the thermal camera and found that the UP701 chip was... -
Greetings to the entire forum, I ask you for help because I'm going crazy. A dear friend of mine gave me a macbook pro M1 A2338 that only works with an external screen. With the internal one, no backlight or image. Only the external display is detected from the system settings.
First I changed the display flat, then I made a backup with time machine and tried a reset in dfu but nothing to do, always the same problem.
I analyzed the logic board, it shows no sign of liquid or visible damage. I then moved on to examine the logic with the thermal camera and found that the UP701 chip was...
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