Why will my machine not re-start?
I have a similar issue to Powers up, no chime, three LEDs, then shuts off.. but with a very slightly different LED sequence.
Early 2008 24” 2.8 GHz Intel iMac; 4GB RAM; EMC No. 2211; Model No. A1225; OS X El Capitan with latest (last) security update (15G22010).
The machine was shut down during a recent vacation and on return it would not start normally. After re-setting SMC or PRAM it would run without a problem. But it required such re-setting after every shutdown.
Yesterday the machine worked fine – it had been on continuously for several days after starting with a PRAM re-set. I reinstalled OS X El Capitan, keeping the user data. Everything looked good and I subsequently closed down and restarted the machine normally 4 – 5 times (no re-sets).
Today the machine would not start. Resetting the SMC and PRAM does nothing. I replaced the PRAM battery. No change.
Symptoms: After pressing the power button I hear a fan operating and the chime starts; however the chime is cut short and the fan noise stops. The machine cannot be re-started until the mains plug is removed and replaced.
LED 1 lights up when it's plugged in. When I push the power button LEDs 2 and 3 light up sequentially. But as soon as LED #4 lights up it turns off, followed very rapidly by LEDs 3, 2 and 1.
Long story but a short question: Is the power supply the culprit, as in Steve Godun’s case, or, because LED #4 is coming on for a split second before all LEDs shut down, is something else in play?
Bulge at end of capacitor C209 second from right:
Maybe slight bulges at end of two black capacitors C214 & C215:
Is this a good question?