Power supply imac 2009 - burnt

Thread Starter

petrisor86

Joined May 22, 2021
11
Hi guys,

Can you please help me or give some advice how to test the Fuse T6.3A 250V. When I’ve replaced cpu of my imac and I installed the display, the flex band v-sync touched the power supply on and blew up. Now I need to replace the electronic parts from the power supply.

I’ve started with the fuse T6.3A 250v from the picture, how can I test it with multimeter?
Thanks in advance
 

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Delta Prime

Joined Nov 15, 2019
996
Hello there welcome to AAC! :)
Unplug your power supply from the wall socket.
On your multimeter or DMM.
Insert the black test lead into the COM jack.
Insert the red lead into the VΩ jack.
Turn the dial to Continuity Test mode. It will likely share a spot on the dial with one or more functions, usually resistance (Ω).
We make sure the DMM is working properly .
With the test probes separated, the multimeter’s display may show OL and Ω.( No beep) .
With the test probes touching each other you should hear a beep.
Place one test probe on one leg of the fuse and the other test probe on the other leg of the fuse the position of the test probes is arbitrary ,does not matter placing the black test probe or red test probe on any leg of the fuse you want.
The digital multimeter (DMM) beeps if a complete path (continuity) is detected . The fuse is good. If it does not beep the fuse is bad no continuity. replace the fuse. You have a slow blow fuse there, that's what the T (Time) indicates on the fuse (T6.3A) replace it with the exact same one. And you're done!:)
 
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Thread Starter

petrisor86

Joined May 22, 2021
11
oh, thank you so much for your good explanation. I’ve tested in the same way you told me above and when I’ve tested with Ω 20k, 200k or 200 simple I get OL, when I want to test with Bep on fuses I don’t have any beep.

I think the fuse T6.3 250v needs to be replaced.

one more thing - when I connect the power supply 220 v , my socket home fuse turns of. Maybe other
electronic parts are blew up.
 

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Yaakov

Joined Jan 27, 2019
3,153
A blown fuse will not be the cause of the receptacle fuse blowing.

Since the fuse appears to be directly on the mains input I can't imagine what could be blowing the receptacle fuse off that fuse is, in fact, open.

It would require a short circuit from the hot mains to ground, is there something on the board doing that?

Can you take a good photo of the other side of the board?
 

Delta Prime

Joined Nov 15, 2019
996
Follow the instructions @Yaakov suggested make sure it is not plugged into the wall outlet. This is very dangerous portion follow instructions to the letter please!
If you have any questions stop what you're doing and ask.
 
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