La memoria RAM no ha superado la comprobación de integridad.
Tres tonos seguidos, pausa de cinco segundos, tres tonos seguidos, no enciende y ya se probaron con varias memorias RAM que si sirven, incluso con las originales y sige el mismo problema,
iMac (Mid 2007) and later models: About startup tones
Summary
iMac (Mid 2007) and later model iMac computers, unlike other Macintosh computers, do not use the power LED to indicate there is an issue. iMac (Mid 2007) and later model iMac computers use tones instead.
Products Affected
MacBook Pro (15-inch, Mid 2009), iMac (20-inch, Early 2008), iMac (20-inch, Early 2009), iMac (20-inch, Mid 2007), iMac (20-inch, Mid 2009), iMac (21.5-inch, Late 2009), iMac (21.5-inch, Late 2012), iMac (21.5-inch, Mid 2011), iMac (24-inch Mid 2007), iMac (24-inch, Early 2008),iMac (24-inch, Early 2009), iMac (27-inch, Late 2009), iMac (27-inch, Late 2012), iMac (27-inch, Mid 2011)
The following table lists the new tones and their meaning:
| Tone(s) | Description |
| 1 tone, a 5-second pause, repeat | No RAM installed |
| 3 successive tones, a 5-second pause, 3 successive tones | RAM does not pass data integrity check |
| 1 long tone when holding down the power button | Firmware upgrade in process. See About firmware updates for Intel-based Macsfor more details. |
| 3 long tones, 3 short tones, 3 long tones | Firmware restoration from CD in process. See About the Firmware Restoration CD (Intel-based Macs) for more details. |
MacBook Pro, iOS 6.0.2