Our team has years of experience in iMac repairs and can diagnose without the need for disassembly.
iMacs are not as prone to the physical damage we see with laptops, more often than not it is one of three issues.
Hard Drive or Solid State Storage
Like a car engine the HDD and SSD storage has a maximum distance it can travel before replacement or service is required. This can be as little as a few years with heavy use or with light use it might go on for a decade.
The sign of HDD failure is most commonly seen in the iMac becoming stuck on the Apple boot logo.
The Graphics Card
The graphics card should go on forever, unfortunately Apple has produced several defective graphics cards over the years. Fortunately for us this is a replaceable component!
A sign that the graphics card has failed is distortion to the display which includes lines, blurred images, strange colours or no picture at all. It can also cause the machine to crash during boot in a similar way to a faulty HDD.
Screens break, it is an unfortunate reality. This can be through physical damage or simply due to internal components failing.
If you hear the boot chime but see nothing on the screen this may be due to screen failure.