Aller au contenu principal

Réparez vos affaires

Droit à la réparation

Pièces & Outils

Powers on then off immediately, bad PSU?

Ok I have a imac a1145 that I bought broken, and initially it would turn on randomly and sometimes the fans would speed up to max rpm. So I took out the logic board and noticed 2 6.3v 1500uf bad caps. I replaced them with good ones, but now the imac will turn on for a split second and turn back off. I noticed on the logic board that the #1 green led indicator is on once the power cord is plugged in and #4 red led indicator turns on after I try to start it. I have looked online for what they mean and have gathered that the #1 is tricky voltage (that's vague), and #4 is overheating. Is the #1 indicator specifically for the PSU or does it cover the logic board too? Any ideas or suggestions would be great, I am at my wits end with it and really don't want to start buying unnecessary parts. Thanks for the help.

Répondu ! View the answer J'ai le même problème

Cette question est-elle utile ?

Score 1


Yeah I'm sure, the striped side is negative and the board is clearly labeled with a + sign for positive. The only thing I can think is that I did not replace the caps with the same physical sized caps. One fits standing as it should and the other I laid on its side and ran wires from the legs to the board. I don't see how that would be an issue but maybe I'm wrong. I did have a bit of trouble getting the one that is standing properly to go back in the holes, so maybe I damaged the cap.


Ok so I replaced the 2 caps again with known good ones, and now it acts a little better when trying to turn on, whereas before it wouldn't always flash the white led and now it always turns the white led on every time but I still got that #4 indicator light on. Is it possible to have a cold joint on either the GPU or CPU causing this? If so would reflowing them with my hot air work station fix it?


Ajouter un commentaire

Kits pour Nintendo Switch

Une solution rapide pour reprendre le jeu

Acheter un kit pour Switch

Kits pour Nintendo Switch

Une solution rapide pour reprendre le jeu

Acheter un kit pour Switch

1 solution

Solution retenue

Here is a link to a previous post with the guide to what the lights mean. From what you describe I wonder if you don't still have one or more bad caps. Are you certain you installed the new caps with the correct polarity? Good luck

Where is a decoder for diagnostic LED pattern?

Cette réponse a-t-elle été utile ?

Score 3
Ajouter un commentaire

Ajouter une réponse

Erick sera éternellement reconnaissant.
Afficher les statistiques:

Dernières 24 heures : 0

7 derniers jours : 1

30 derniers jours : 2

Total : 1,756