21.5" (iMac 10.5 downgrade) External Monitor No Workie?

[StrongBone]

Heyo,
I have just completed the snow leopard de-stall on a 21.5" iMac. (By that I mean I reformatted and installed 10.5)

Two machines now both with the same result. After installing Leopard and all of the updates the external display port no longer detects 2nd monitor as it did with Snow.

Any suggestions? (other than upgrading to Snow)

iMac10,1
Installation Disk: [Mac OS X Leopard (install DVD) v10.5.6]

Thanks~

 

[flopticalcube]

Since Leopard was never designed with your iMac in mind, its small wonder some things don't work. Do you have the 9400m or the 4670 graphics?

 

[Hellhammer]

As your iMac came with Snow Leopard, it's the only OS X that it supports...

Leopards doesn't have all the drivers your iMac needs to work properly

 

[StrongBone]

Do you have the 9400m or the 4670 graphics?

4670

 

[Hellhammer]

4670

It wasn't used before Snow Leopard came out so Leopard simply has no drivers for it, that's why external monitors won't work

 

[flopticalcube]

It wasn't used before Snow Leopard came out so Leopard simply has no drivers for it, that's why external monitors won't work

Word!

 

[tersono]

Your Mac requires Snow Leopard for full driver support.

Given that SL is faster and more stable than Leopard, I can't even begin to contemplate why you would have downgraded...

 

[StrongBone]

absolutely correct (confirmed by apple support)

Thanks for the input everyone!

 

[StrongBone]

Given that SL is faster and more stable than Leopard, I can't even begin to contemplate why you would have downgraded...

I am troubleshooting a issue in our laboratory, I have a handful of domained Macs that are having issues saving files to a M$ server, I have a similar group of Macs that have 10.5 and they have no issues saving. Tried a bagillion different methods to correct the issue(s) and then decided to try and eliminate the common...
And now we know this can be done successfully.

 

[Hellhammer]

I am troubleshooting a issue in our laboratory, I have a handful of domained Macs that are having issues saving files to a M$ server, I have a similar group of Macs that have 10.5 and they have no issues saving. Tried a bagillion different methods to correct the issue(s) and then decided to try and eliminate the common...
And now we know this can be done successfully.

Have you called AppleCare and asked if they knew a solution for it? It's at least worth it to tell them that it exists so it can be fixed in future