Why are you trying to replace things without knowing what is wrong? Have you measured or are you just guessing? This gets nothing done. We do not randomly replace things with no knowledge of a circuit. We seek to understand how it actually works, measure, think, and repair. Last I checked address bar it said ifixit not iguessandfuckitup.
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Why are you trying to replace things without knowing what is wrong? Have you measured or are you just guessing? This gets nothing done. We do not randomly replace things with no knowledge of a circuit. We seek to understand how it actually works, measure, think, and repair. Last I checked address bar it said ifixit not .
Most "common" problem is ball A5 on LP8550 or LCD connector, but guessing is BS and should not be done here.
put multimeter in diode mode, red probe on ground, black probe on pins 3/4 of LCD connector.
- 0.0 or 0.007 means direct short to ground, usually inside LCD connector or LCD cable.
- 0.200-0.300 is bad LED driver.
- 0.459-0.511 is bad feedback via or corroded away feedback ball under LP8550
- 0.565 is corroded solder ball or bad switch trace inside LP8550
Measure voltage along each point in the circuit. Before F9700, after F9700. At output.
At output,
- 0v means short to ground, blown fuse, or no LCD conected. Check that you see an image on the LCD, check backlight fuse, check board via from FET after fuse to boost coil.
- 8v means no short to ground, good fuse, but no boosting. Check BKL_EN is 2.7 to 3v at voltage divider going to enable pin of WLED driver, check BKL_PWM signal exists.
- 27v or higher means all good, but your LCD cable or LCD backlight itself is blown.
If you see power along the line, where is it? Where does it stop?
If you replace a fuse with a short to ground anywhere in the line you have wasted your time, and a precious little 0603 package. :(
In terms of where to buy fuses, if only there were a document that told you the exact voltage, amperage and package size of them.....
Lastly if it worked for a few months and then died most likely your problem is on bad feedback via/ball on LP8550, pins 3/4 coming corroded on LCD connector, or BKL_EN voltage divider resistors in that order.
Why are you trying to replace things without knowing what is wrong? Have you measured or are you just guessing? This gets nothing done. We do not randomly replace things with no knowledge of a circuit. We seek to understand how it actually works, measure, think, and repair. Last I checked address bar it said ifixit not iguessandfuckitup.
Most "common" problem is ball A5 on LP8550 or LCD connector, but guessing is BS and should not be done here.
put multimeter in diode mode, red probe on ground, black probe on pins 3/4 of LCD connector.
- 0.0 or 0.007 means direct short to ground, usually inside LCD connector or LCD cable.
- 0.200-0.300 is bad LED driver.
- 0.459-0.511 is bad feedback via or corroded away feedback ball under LP8550
- 0.565 is corroded solder ball or bad switch trace inside LP8550
Measure voltage along each point in the circuit. Before F9700, after F9700. At output.
At output,
- 0v means short to ground, blown fuse, or no LCD conected. Check that you see an image on the LCD, check backlight fuse, check board via from FET after fuse to boost coil.
- 8v means no short to ground, good fuse, but no boosting. Check BKL_EN is 2.7 to 3v at voltage divider going to enable pin of WLED driver, check BKL_PWM signal exists.
- 27v or higher means all good, but your LCD cable or LCD backlight itself is blown.
If you see power along the line, where is it? Where does it stop?
If you replace a fuse with a short to ground anywhere in the line you have wasted your time, and a precious little 0603 package. :(
In terms of where to buy fuses, if only there were a document that told you the exact voltage, amperage and package size of them.....
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Lastly if it worked for a few months and then died most likely your problem is on bad feedback via/ball on LP8550, pins 3/4 coming corroded on LCD connector, or BKL_EN voltage divider resistors in that order.
Why are you trying to replace things without knowing what is wrong? Have you measured or are you just guessing? This gets nothing done. We do not randomly replace things with no knowledge of a circuit. We seek to understand how it actually works, measure, think, and repair. There is a reason this is called ifixix and not iguessandfuckitup.
+
Why are you trying to replace things without knowing what is wrong? Have you measured or are you just guessing? This gets nothing done. We do not randomly replace things with no knowledge of a circuit. We seek to understand how it actually works, measure, think, and repair. Last I checked address bar it said ifixit not iguessandfuckitup.
Most "common" problem is ball A5 on LP8550 or LCD connector, but guessing is BS and should not be done here.
put multimeter in diode mode, red probe on ground, black probe on pins 3/4 of LCD connector.
- 0.0 or 0.007 means direct short to ground, usually inside LCD connector or LCD cable.
- 0.200-0.300 is bad LED driver.
- 0.459-0.511 is bad feedback via or corroded away feedback ball under LP8550
- 0.565 is corroded solder ball or bad switch trace inside LP8550
Measure voltage along each point in the circuit. Before F9700, after F9700. At output.
At output,
- 0v means short to ground, blown fuse, or no LCD conected. Check that you see an image on the LCD, check backlight fuse, check board via from FET after fuse to boost coil.
- 8v means no short to ground, good fuse, but no boosting. Check BKL_EN is 2.7 to 3v at voltage divider going to enable pin of WLED driver, check BKL_PWM signal exists.
- 27v or higher means all good, but your LCD cable or LCD backlight itself is blown.
If you see power along the line, where is it? Where does it stop?
If you replace a fuse with a short to ground anywhere in the line you have wasted your time, and a precious little 0603 package. :(
In terms of where to buy fuses, if only there were a document that told you the exact voltage, amperage and package size of them.....
Why are you trying to replace things without knowing what is wrong? Have you measured or are you just guessing? This gets nothing done. We do not randomly replace things with no knowledge of a circuit. We seek to understand how it actually works, measure, think, and repair. There is a reason this is called ifixix and not iguessandfuckitup.
Most "common" problem is ball A5 on LP8550 or LCD connector, but guessing is BS and should not be done here.
put multimeter in diode mode, red probe on ground, black probe on pins 3/4 of LCD connector.
- 0.0 or 0.007 means direct short to ground, usually inside LCD connector or LCD cable.
- 0.200-0.300 is bad LED driver.
- 0.459-0.511 is bad feedback via or corroded away feedback ball under LP8550
- 0.565 is corroded solder ball or bad switch trace inside LP8550
Measure voltage along each point in the circuit. Before F9700, after F9700. At output.
At output,
- 0v means short to ground, blown fuse, or no LCD conected. Check that you see an image on the LCD, check backlight fuse, check board via from FET after fuse to boost coil.
- 8v means no short to ground, good fuse, but no boosting. Check BKL_EN is 2.7 to 3v at voltage divider going to enable pin of WLED driver, check BKL_PWM signal exists.
- 27v or higher means all good, but your LCD cable or LCD backlight itself is blown.
If you see power along the line, where is it? Where does it stop?
If you replace a fuse with a short to ground anywhere in the line you have wasted your time, and a precious little 0603 package. :(
In terms of where to buy fuses, if only there were a document that told you the exact voltage, amperage and package size of them.....