iMac (Mid-2007): Random shutdowns, possible fix; FireWire chipset changed? Problems with daisy-chained devices
An SMC reset might help.
Random shutdowns, possible fix Some users are reporting random shutdowns from Mid-2007 iMacs. The reports we've received mimic a similar issue with the MacBook that was resolved with an Apple-isued SMC firmware update. As such, users experiencing this issue might want to try resetting the SMC via these steps:
- Turn the computer off
- Unplug all cables from the computer, including the power cable and any external device cables.
- Wait 30 seconds.
- Plug the computer back in and connect the keyboard/mouse, then turn it back on.
One reader writes:
"I have an iMac 20' screen 2.4 GHz with 2 GB RAM (originals from Apple) and in two weeks it suddenly shutdown during a normal operation twice. The screen turns black like a power failure occurred but I have a APC nobrake perfectly working."
The problem could also be improperly seated RAM modules. Try removing the RAM modules then firmly seating them back in place.
As described in Apple Knowledge Base document #303083:
"If the computer detects no SDRAM (Synchronous Dynamic Random Access Memory, also referred to as RAM) or the RAM installed does not meet the appropriate specifications, the screen will remain black but the power LED on the front of the computer will blink once per second to signal the error. This error condition may be due to physically damaged RAM, installing the incorrect type of RAM, or not having RAM installed."
If you are experiencing a similar issue, please let us know.
FireWire chipset changed? Problems with daisy-chained devices Some users are reporting problems with daisy-chained FireWire devices and the new iMac -- an issue that didn't exist with older models, possibly indicating a change in the FireWire chipset used by the new models.
MacFixIt reader Kelvin Ritchie writes:
"I've got a new Aluminum iMac 20" 2.4ghz. I've got two external OWC FW 400 7200 rpm hard drives which are daisy chained together. One is a backup drive and the other is a video storage hard drive for my iMovie files. The chain is: iMac --- Backup drive --- Video drive. I connect my Canon Elura 100 DV camcorder, a standard definition camcorder, to the open FW port on the Video HD: iMac --- Backup drive --- Video drive---Camcorder. The data path would be: Camcorder---Video HD---Backup HD---iMac---iMovie 08---Backup HD---Video HD
"When I try to import video with iMovie 08 and save it to the external Video hard drive I get a lot of dropped frames. The same issue occurs when trying iMovie 06 HD. If I import it to the internal hard drive I believe I'm getting a clean import. If I connect just the Video drive to the iMac and then the camcorder to the Video drive and try to import to the Video drive I still get frame loss. If I import to the internal drive then I get a clean import."
"Prior to getting my iMac I used iMovie 06HD on my G4 iBook 1.2ghz running 10.4.10 using the same FW configuration above and never dropped any frames. I retested the configuration above with the iBook to my FW drives and got a successful import. I have to now assume there is an issue with my FW 400 port."
Feedback? Late-breakers@macfixit.com.
Previous coverage:- iMac (Mid-2007): Repeated crashes after Software Update 1.1; graphics-related
- iMac Software Update Released
- iMacs (Mid-2007) [#4]: Screeching noise; Problems with old keyboards/mice?
- iMacs (Mid-2007) [#3]: More on FireWire target disk mode not working; fixes
- iMacs (Mid-2007) [#2]: FireWire problems: Target disk mode and others (cont.); screen issues
- iMacs (Mid-2007): Problems with FireWire target disk mode; Condensation under glass
Resources