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Hi Everyone,
No start, nothing when press power button. Looked at leds.
Plugged imac into power and led#1 comes on. When press power button, led#1 goes out.
Replaced power supply.
Now, plugged imac into power and led#1 comes on. When press power button, led#2 flashes on, screen flashes briefly, then both leds go out.
Would anyone have some insight into this problem?
thanks,
Dave
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Sounds like your power supply has failed.
LED #1
Indicates that the trickle voltage from the power supply has been detected by the main logic board. This LED will remain ON whenever the iMac is connected to a working AC power source. The LED will remain on even when the computer has been shut down or put to sleep. The LED will turn off only if the AC power source is disconnected or the power supply is faulty.
LED #2
Indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON (turn on and remain on) when the computer is turned on and the power supply is working correctly.
LED #3
Indicates that the computer and the video card are communicating. This LED will be ON (turn on and remain on) when the computer is communicating properly with the video card. If LEDs 1 and 2 are ON and you heard the startup sound, but LED 3 is OFF, then the video card might be installed incorrectly or need replacement.
LED #4
Indicates that the computer and the LCD display panel are communicating. This LED will be ON (turn on and remain on) when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement.
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Thanks, Mayer. So the second power supply is bad, maybe. I got the power supply from an ebay supplier that claimed that the PS was new. Looks new, no burns, bulges, or other. I guess that I will measure voltages for the new PS and the old PS. Could something else in the computer be drawing so much current that the new PS gets fried?
Does the machine try to restart after you power it on the first time?
No. Nothing happens, no sounds, except for the leds and the transitory screen flash, which can't really be called a flash, just the glimmer of a little light. The screen does not light up.
I noticed that the fan tries to turn, when I push the power button when I have it open.
Sounds like you're getting the trickle power from a failed power supply. How did the multimeter tests come out on it?
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3 Comments
I did not do the multimeter tests yet. I emphasize that I have replaced the power supply with a new one from a sealed package. There was no change with the new PS, except maybe now there is a little twitch of the fan. But I might not have noticed that with the original PS.
by dgarboczi
I'm back on this project after 6 months. I get LED #1 upon plugging in, then when turn on, #2 and #3 come on briefly and then all three go out. I would like to test the power supply with voltmeter, but it's the 614-0405 power supply for the A1225 24". There are two rows of six output terminals (12 total). The "iMac Intel 20" EMC 2210 Power Supply Output Voltage Test" shows one row of 10 terminals. Can anyone tell me what volts I should be seeing on which terminal? The terminals are numbered on the board.
thanks,
Dave
by dgarboczi
I replced a CPU (upgrade to i7/3.4 GHz) . Got LED 1 ON, LED 2 briefly on then off (cycles) , measured everything. had to find out one or more RAM modules weren't seated correctly or were dirty at contactlevel. Cleaned, reseated firmly, Got it all back up working again , was about to throw it out the window :)
by Hk Barry