Hi all,
have another iMac with flickering then black screen issue.
It is a 21.5" 2010 A1311 model.
When switched on, the screen flickers before going black. With a torch you can see the image is there, as are all four diagnostic LED's.
Measuring the PSU output only gives around 10.5v with the cable harness connected, although it measures 12.06v unconnected. This leads me to suspect something the power supply.
I saw that some people had found a shorted mosfet on the output however these seem fine, when tested for shorts on the board.
There are two power-Schottky rectifiers which although the datasheet gives the Forward Voltage at 0.57v, are only reading around 0.19v across all four.
So my question is, "could these low Schottky readings cause the PSU output to drop under load?
Thanks in advance
have another iMac with flickering then black screen issue.
It is a 21.5" 2010 A1311 model.
When switched on, the screen flickers before going black. With a torch you can see the image is there, as are all four diagnostic LED's.
Measuring the PSU output only gives around 10.5v with the cable harness connected, although it measures 12.06v unconnected. This leads me to suspect something the power supply.
I saw that some people had found a shorted mosfet on the output however these seem fine, when tested for shorts on the board.
There are two power-Schottky rectifiers which although the datasheet gives the Forward Voltage at 0.57v, are only reading around 0.19v across all four.
So my question is, "could these low Schottky readings cause the PSU output to drop under load?
Thanks in advance
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