Mac Mini won't recognise External Hard Drive

Hi folks, I've been wandering round this site for ages and finally decided to join in with my wee query.

I have an old mac mini and lately it doesn't recognise any of my hard drives (3 different makes of hard drive). I have repaired the disks on the external hds on my mac in work (where all the hard drives are recognised so ain't the hard drives problem) and repaired permissions on my mac mini at home but still no joy. Tried to repair the internal disk by putting in the osx (Leopard) cd-rom but it couldn't dismount the internal harddrive.

Any suggestions as to what it could be? Bit of a pain as I'm waiting till November to update to a macbook pro

What is the format of the external drives? Are they USB powered or use a power adapter?

And whilst USB may recognise them, if the mini is a G4 will require a Firewire connection to boot from them and also drives need to be set up in Apple Partition Map, even if only one partition, and Mac OS Extended (Journalled).

Thanks Harry, just seen your reply now, sorry. All three of my external hard drives used to be recognised and nothing changed with them so it's a problem with the mini I presume. They are Mac OS Extended and it is a G4 mini. Not sure about the Apple Partition Map and can't check at the mo but as I said they have all stopped working just recently. They are all USB too.

Do you not get an email to remind you to check your thread here or do I need to tick a box?

Thanks again, DC

Be sure you are subscribed to the thread and you will get an email when the next post is posted. You use thread tools up top of this thread or go into your settings here at mac forums and set it to always subscribe you to threads you are active in.

I have a older Power PC G4 Mini and so far every external mounts on it with no issues both with 10.4 Tiger and 10.5 Leopard.

I'm very happy for you. I'm on Leopard and having problems....

Anyone have any idea why this is happening? Any advice welcome...

Take it the external drives have their own main power sources as it does sometimes happen drawing power from the USB port drags too much power and they fail? Next it sounds like you are having a USB cable or port problems. Check all the pins are nice and straight and nothing has become bent.

What does Apple System Profiler say about USB?