2012 iMac stuck on white screen + no keyboard - options?

[sintholo]

Model is Late 2012 21.5" iMac.

A bit of background that may be relevant, but I'll keep it brief:

• It has a bootcamp partition with Windows 7
• I believe the drive was failing, as the mac partition (Mavericks) crashed over a year ago and I wasn't able to fix that through any methods.
• I had finally gotten all my data off & was ready to erase the drive when the white screen started. I tried many troubleshooting options that I could find but none worked.
• I replaced the drive hoping that would change it, it didn't.
• The keyboard stopped registering when the white screens started & still won't register after the new drive (I know because the caps lock key no longer lights up on boot). Mouse is fine.
• I have a boot drive for High Sierra that I made, but it won't boot past white screen with or without this plugged in.

Basically I want to know what my options are here in terms of fixing this *without* a keyboard, and if I can't fix it is it worth taking to a professional? Should I keep the new drive or is that not the problem?

 

[chscag]

See the reply given in the other forum where you posted this same thread.

 

[vkd]

If your keyboard is Apple Magic Keyboard v1, upon pressing the Power button on your mac, press the bluetooth activate button on it to make that little green light illuminate before you quickly press and hold down the Option key to bring you to the Startup Chooser. See if the internal drive appears. If not, there is a problem with it (still).

Plug an external USB HDD in and using the above method to verify it connects at boot, go about installing the OS on that.