Mac makes start sound monitor stays black.

Okay, the options are to get yourself a new Mac mini, you can still use your keyboard and mouse from your iMac and will only need a display (about $100) and for about $1000 you have a nice replacement that is brand new, includes a warranty and is eligible for AppleCare.

Another option is buy an Apple Refurbished Mac from Apple.com - Go to the bottom of the page and select - Refurbished and Clearance. There is NO downside to buying one of these. They are identical to a new Mac, have the same warranty as new, are eligible for AppleCare and can save hundreds of $$. If you take this route, only buy one with 16GB of RAM and ANY that you select buy one with the largest SSD you can afford. DO NOT buy one with a hard drive or a Fusion drive.

Third option is to buy a used Mac from a reputable reseller such as Macsales.com. Never buy from Ebay and Amazon reseller etc. The upside of used is you save a LOT of $$ and if you buy from Macsales.com you can still customize the computer to get a SSD, more RAM and it will come with some warranty.

A computer from about 2002 is so antiquated you are extremely limited on what software it will run, it cannot run any near a current version of Mac OS, it has zero value and parts are simply not available. In short it has had its day and it is time to replace it.

Hello and welcome to the Apple Support Communities, Macblackscreen9.

We understand that your Mac is starting to a black screen, so we'd like to help. It appears that you've had a chance to review If your Mac doesn't start up all the way, which is a great. If your Mac starts up to a blank screen has some steps to try, including using Disk Utility to repair your startup disk.

Reply to this message if you need more help.

Cheers!

Macblackscreen9,

Thanks for the reply. The best step forward would be to take your iMac to an Apple Store or Apple Authorized Service Provider to have it evaluated. If needed, this link will help you find a store near you: Find Locations. You can also reach out to Apple Support directly. They can be reached here: Get Support, or by calling the most applicable phone number listed here: Contact Apple for support and service.

All the best!

Follow the steps explained above, however it is likely a hardware failure. If your iMac is a 2013 or earlier iMac I would spend your resources on replacing it. The reason being is 2013's are considered vintage by Apple which means parts are not available and an Apple Store will not work on it because of that. In addition a 2013 and earlier will not run current versions of Mac OS.

If you don't want to buy a new iMac then let us know as there are many alternatives available to you.

Try this: https://discussions.apple.com/thread/6768724

there are loads of different suggestions and tips in that link.

but make sure you follow the steps closely.

Macblackscreen9,

Sure thing. If you need any help in the future, feel free to post again.

Take care.