Testing a power supply

Question

iMac Intel 21.5" EMC 2428

모델 A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 또는 2.8 GHz Core i7 프로세서

432 질문 전체 보기

Adam @moon_man157

평판: 25

1

게시일: 2016년 7월 14일

옵션

Testing a power supply

My iMac will not power on, the diag LED’s do not turn on ether. I’d like to test the power supply independently of the logic board. I know how to cross pins on a standard ATX power supply and verify functionary but they have 20 pins and most are color coded. The power supply in the iMac only has 14 pins and there are no voltage or polarity markings I can see. I’ve looked quite a bit online and have been unable to find a pin-out of the EMC 2428 iMac power supply. Can someone please point me in the right direction?

답변되었습니다! 답변 보기 저도 같은 문제를 겪고 있습니다

좋은 질문 입니까?

예 아니요

점수 2

댓글 달기

답변 1개

선택된 답변

Dan @danj

평판: 479.4k

Self employed contract worker

35

329

971

게시일: 2016년 7월 14일

옵션

If the diagnostic LED's aren't lighting up and you're sure you have a good cord and power at the outlet it's a slam-dunk here your power supply is gone, time for a new one.

Diagnostic LED’s

해당 답변은 도움이 되었습니까?

예 아니요

점수 2

댓글 9개:

Thanks Dan.

Yes, I’m sure the A/C to the power supply is good and just for good measure I tested the power button. The power button is fine but I thought something might be wrong with the logic board which might stop the signal from getting to the power supply. Are you saying that if the power supply were good there should be some responds from the diag LED’s no matter how bad the logic board may be?

Adam 의 2016년 7월 14일

Yes, the soft switch logic is on the power supply unit not the main logic board. Review the info in the link ;-}

Dan 의 2016년 7월 14일

iMac Intel 21.5" EMC 2428 Power Supply Replacement

iMac Intel 21.5" (Late 2009-Mid 2011) Power Supply

mayer 의 2016년 7월 14일

Thanks Mayer for adding the links!

I should add many power supplies get killed by bad power or lightning strikes. Best to get a good surge suppressor or a UPS. We opted for UPS's, we saw a dramatic reduction of burnt PS's.

Dan 의 2016년 7월 14일

A UPS can also prevent hard drive writing errors. I found this especially true in old parts of town where power supply lines or transformers don't supply a clean steady flow. If you get the lights dimming when air conditioners come on, you have a probable issue with this.

mayer 의 2016년 7월 15일

댓글 4개 더보기

댓글 달기

Thanks Dan.

Yes, I’m sure the A/C to the power supply is good and just for good measure I tested the power button. The power button is fine but I thought something might be wrong with the logic board which might stop the signal from getting to the power supply. Are you saying that if the power supply were good there should be some responds from the diag LED’s no matter how bad the logic board may be? — Adam
Yes, the soft switch logic is on the power supply unit not the main logic board. Review the info in the link ;-} — Dan
iMac Intel 21.5" EMC 2428 Power Supply Replacement

iMac Intel 21.5" (Late 2009-Mid 2011) Power Supply — mayer
Thanks Mayer for adding the links!

I should add many power supplies get killed by bad power or lightning strikes. Best to get a good surge suppressor or a UPS. We opted for UPS's, we saw a dramatic reduction of burnt PS's. — Dan
A UPS can also prevent hard drive writing errors. I found this especially true in old parts of town where power supply lines or transformers don't supply a clean steady flow. If you get the lights dimming when air conditioners come on, you have a probable issue with this. — mayer

iMac Intel 21.5" EMC 2428

Testing a power supply

답변 1개

귀하의 답변을 추가하세요