g5 noisy fan, red light

Hi, and a Warm Welcome to Apple Discussions and the Power Mac G5 Forum!

Well - you don't say which G5 you have - there's a list here

http://support.apple.com/specs/powermac/

Assuming it's not a "Late 2005" dual-core G5

http://support.apple.com/specs/powermac/PowerMac_G5_Late2005.html

which has several LEDs on the main logic board - explained here

http://docs.info.apple.com/article.html?artnum=302527

you could try a test: when the G5 is running normally - i.e. no roaring fan and LED - take off the aluminium side panel (should not affect the fans) and then pull the clear plastic deflector panel outwards from the top with the handle, and then tilt it forwards so that rear-most locating peg on the bottom edge of the deflector panel just clears the slot in which it normally sits.

If you then get exactly the symptoms which are the problem - red LED on the front (left as you look at from the side) edge of the main logic board (just behind the power switch and front external sockets), and the roaring fan (it's actually just the Drive Bay fan that goes into hyperdrive - as a warning) - then it's possible the silver/white tab on the rear-most locating peg of the clear plastic deflector panel is damaged or defective. Some diagrams here

http://www.info.apple.com/usen/cip/pdf/g5/073-0891.pdf

If the label is damaged you can substitute a piece of shiny gift wrapping tape, as explained here

http://discussions.apple.com/thread.jspa?messageID=2658261&#2658261

which also mentions using a torch/flashlight to check whether the sensor inside the slot itself is ok; more detail, plus cleaning the sensor with a can of compressed air, here

http://discussions.apple.com/thread.jspa?messageID=2996565#2996565

Please post again if you have any questions - or if this isn't the solution. Good Luck.

Hi. Well - I don't know about "safe to assume" - this is a computer we're talking about...!

However, as the normal operation of the sensor is that it only triggers when the dust cover/air deflector is removed - it's possible that, if the current situation is that the fan/LED on your machine is now 'on' all the time, even when your colleague's dust cover/air deflector, with a presumed-good reflective label, is in place on your G5 - it does seem likely that there is a problem with the sensor - officially the "Air Deflector Sensor Board".

It's possible that spraying the air has dislodged a connector that was only just making contact - hence the previously intermittent nature of the symptoms. Or that the sensor is duff, of course.

Hope we are not jumping to any conclusions as to the cause - but it sounds like one for the shop.

Please post again if this isn't quite the current situation - e.g. the fan/LED is not now 'on' all the time. Good Luck.

Forgot to mention (and couldn't edit...) - as the Air Deflector Sensor Board is glued in place, it may just have come unstuck.

I have the same issue, except that I have a late 2005 model.
Would you be able to help?

Hi Rick1001, and a Warm Welcome to Apple Discussions and the Power Mac G5 Forum!

Only just seen your post - which is a very good reason to post a new question of your own in this Forum, so that it gets noticed - linking to this thread if helpful.

If you give as much info as you can - exact model G5, OS X version, any previous form, any changes made prior to the phenomenon, what exactly you see and hear (presumably some LEDS

http://docs.info.apple.com/article.html?artnum=302527

are on), what steps you have taken to try to fix it, etc., it will help.

Good Luck.