옵션

Weird issue with starting up

I’m having an issue with this hand-me-down iMac I got a while ago. It will only start up if the screen is disconnected from the logic board and if I hold the power button down while it is starting up.

iMac starting up when screen is disconnected:

iMac starting up when the screen is connected

This completely baffles me. I have still yet to try connecting the iMac to an external display, but here is what I have tried:

Reseating the RAM (the RAM is known-good)
Replacing the PRAM battery

Does anyone have any ideas of what could be going on here? I’m leaning towards either a logic board or a display issue.

Alright so I played in the guts of this iMac and snooped around looking for swollen or leaking caps. I found none that appeared to be too swollen but there were definitely some caps that were a teensy bit bigger then the rest. Have we found the root of the problem?

답변되었습니다! 답변 보기 저도 같은 문제가 있습니다

좋은 질문입니까?

예 아니요

점수 0

댓글 달기

게시됨: 2019년 1월 31일

옵션

Examine the capacitors on the logic board (cans). Look for leaking and/or swollen ones.

이 답변이 도움이 되었나요?

예 아니요

점수 4

댓글 12개:

Quick question, not trying to shoot you down here but wouldn't the capacitors be on the power supply instead of the logic board?

tr121 의 2019년 1월 31일

What are the diagnostic LEDs on the center of the logic board telling you? The reason I want you to look at the capacitors is that it is a very well known issue and i have seen a lot of these. Yes the power supplies do fail a lot on these but your symptoms indicate the caps.

mayer 의 2019년 1월 31일

Alright, thanks for the clarification. I’ll take a look at the caps on the L-board and the PSU once I get home. Are the diagnostic LEDs in the videos not the ones we are looking for?

tr121 의 2019년 1월 31일

@mayer updated answer

tr121 의 2019년 1월 31일

Your picture shows a failed or failing capacitor.

mayer 의 2019년 1월 31일

댓글 7개 더보기

댓글 달기

iMac Intel 17"

Weird issue with starting up

Update (01/31/2019)

답변 1개

답변을 추가하세요