Suspected faulty PSU

[spacebiscuit]

Hi,

I have an iMac with a suspected faulty psu.

If I use a mutli-meter on the two solder points where the plug with 2 wires connects (bottom right corner when fitted) this will just tell me if I am getting power to the PSU is that correct? If there is a fault in the PSU I need to test the pin-outs is that correct?

I have no LED's whatsoever, no fans or any signs of life.

I'm not an electrical expert - so just would like to confirm my logic is correct.

Thanks.

 

[4sallypat]

Yes, if the power is arriving into the PSU, line voltage is what you should see.
After the fuse, and preconditioning filters, the PSU will output various DC voltages.
Make sure your multi meter is set for AC on the input/high voltage and DC for the output side.

Before probing around, reset the PSU by disconnecting the power cord, pressing the power button down for 5 seconds to discharge any stray capacitive charge.

Try disconnecting the PSU DC cabling from the logic board and testing for DC voltage.

Be very careful around the high voltage side.

 

[Nguyen Duc Hieu]

Hi,

I have an iMac with a suspected faulty psu.

If I use a mutli-meter on the two solder points where the plug with 2 wires connects (bottom right corner when fitted) this will just tell me if I am getting power to the PSU is that correct? If there is a fault in the PSU I need to test the pin-outs is that correct?

I have no LED's whatsoever, no fans or any signs of life.

I'm not an electrical expert - so just would like to confirm my logic is correct.

Thanks.

No LED mean the PSU does not receive any power, or PSU is not working, as stated by the Apple Technician Guide.

 

[awsom82]

Hi,

I have an iMac with a suspected faulty psu.

If I use a mutli-meter on the two solder points where the plug with 2 wires connects (bottom right corner when fitted) this will just tell me if I am getting power to the PSU is that correct? If there is a fault in the PSU I need to test the pin-outs is that correct?

I have no LED's whatsoever, no fans or any signs of life.

I'm not an electrical expert - so just would like to confirm my logic is correct.

Thanks.

I have a late 2009 imac^ and in September 2020 it freezes, but after reboot could not load, only in safe mode. I think it was a PSU failure, but it was GPU. Check local Apple repair company, they may figure out what problem for a small amount of money or even free.

 

[spacebiscuit]

Thanks for the replies, I have stripped the imac down completely, removed the logic board and have blown all the dust out - reassembled and just waiting for a replacement PSU to arrive. Hopefully that is the issue - I will post the results once fitted.