I purchased a faulty LG 42PC1D in an effort to teach myself more about electronics.
The power supply had 9 bad caps which have been replaced and I also found a blown fuse on the YSUS. I have removed the IPM and have been trying to check some components as other threads have suggested the IPM might not be the only problem. In the picture attached there are 4x2001N3D Fast recovery Diodes that I have been checking. Am I checking these correctly?
I check what I believe is a forward voltage drop between pins 3 and 2, and also between pins 3 and 1. On the 3 diodes marked with a pink square the readings are all virtually the same with a voltage drop of 0.326v, but when I test the diode with the pins I have marked (1,2 and 3) I get a voltage drop of 0.338v between pins 3 and 2 , and also 3 and 1. I would have assumed this reading was acceptable(if it was the only diode of this type on the board), but because I have 3 more of the same diode to compare to I have noticed a difference even though it is only 0.012v difference. I then checked continuity from pins 1 and 2 to GND(marked with a 4 in the attached pic) and found they both had continuity. I am assuming this is the probable cause of the blown fuse?
Are my measurements and assumption correct? I'm curious as like I said early I would have measured the (suspect faulty) diode with a forward voltage drop of 0.338 and assumed it was ok and not checked anything else.
Can anyone suggest an equivalent to replace this diode with?
Any guidance is very much appreciated.
The power supply had 9 bad caps which have been replaced and I also found a blown fuse on the YSUS. I have removed the IPM and have been trying to check some components as other threads have suggested the IPM might not be the only problem. In the picture attached there are 4x2001N3D Fast recovery Diodes that I have been checking. Am I checking these correctly?
I check what I believe is a forward voltage drop between pins 3 and 2, and also between pins 3 and 1. On the 3 diodes marked with a pink square the readings are all virtually the same with a voltage drop of 0.326v, but when I test the diode with the pins I have marked (1,2 and 3) I get a voltage drop of 0.338v between pins 3 and 2 , and also 3 and 1. I would have assumed this reading was acceptable(if it was the only diode of this type on the board), but because I have 3 more of the same diode to compare to I have noticed a difference even though it is only 0.012v difference. I then checked continuity from pins 1 and 2 to GND(marked with a 4 in the attached pic) and found they both had continuity. I am assuming this is the probable cause of the blown fuse?
Are my measurements and assumption correct? I'm curious as like I said early I would have measured the (suspect faulty) diode with a forward voltage drop of 0.338 and assumed it was ok and not checked anything else.
Can anyone suggest an equivalent to replace this diode with?
Any guidance is very much appreciated.
Attached Files
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