Seek Wisdom for Saving my “iMac” (or, help me fix this White Elephant)

I will apologize in advance for such a lengthy post, but some things just can’t be explained in a few words. Also I am new to this forum and don’t know if this post is acceptable or not. I’m sure someone will let me know.

As of the last week in February 2018, I became the (un?) proud owner of an Apple iMac Intel "Core Duo" 20”/2.0 GHz, EMC-2105. Ser# QP6170GGU23. Standard RAM has been upgraded to 2 GB, when or by whom I don’t know. Radeon X1600 Video Card was an upgrade at time of purchase (assumption) from 128 MB to 246 MB.

Let me begin by saying that I knew absolutely nothing about an Apple iMac, (other than their reputation) when it was given to me by a golf buddy with the following info; It was passed on to him somewhere in the neighborhood of 2007-2008 from his son, and he had been using it up until 6 months ago when his son upgraded him to a newer model iMac, at which time he unplugged it and put it on a shelf. He had always been happy with it and “it was working great when he stopped using it”. He has no documentation, manual, start up discs, nothing, and did not know the OS, version, zip. I have a Mac, power cord, wireless keyboard, and a wireless Mighty Mouse.

So I brought it home, plugged it in, waited for the chime and the boot……...and nothing……..but a Black Screen. No chime, no sounds at all, nothing but the little white glowing indicator light below the right corner of the screen. (Which according to the owner’s manual found online, indicates it’s in sleep mode?) And can’t get it to wake up!

I’ve been using computers since the late 80’s I think, and all have been desktop PC’s. Apple prices have always been beyond my budget. Other than a few memory upgrades, and fan replacements, I’ve left repairs to a repair technician. My technical abilities are not in question. When my 10 yr old iPod Classic recently crashed, the only thing Apple I have ever owned, I totally refurbished it. (with the help of “ifixit” I should add) So I feel pretty comfortable with tearing into this thing, and finding out what makes it un-tick. I will probably need help in the computer knowledge area with terms and lingo I don’t understand.

As a Retired Senior, I have been a craftsman for a long time, and I love to fix things, especially if it’s a challenge, and cost effective. I know I can purchase a working iMac for what I may spend to repair this one, but I need a new project so I think I want to fix this one if I can, and I will have a new hobby to work on when I can’t golf. Am I totally nuts? Is it worth it? Just don’t try to send me to Apple, I won’t go!

First off, with some help, I need to figure out what’s wrong with it to start with. I’ve already covered a lot of ground online through various forums and Apple discussions, and here is what I’ve tried so far that has not worked to solve the problem.

1. Replaced batteries in wireless keypad and mouse. I’m pretty sure they are communicating with the computer in that the little green lights seem to blink at appropriate times.

2. I have removed and replaced the (2) RAM memory cards twice to make sure they were inserted properly. (At this point I don’t know whether they are good or bad.) Purchased (2) new ones, but don’t know why.

3. As previously stated, I don’t have the appropriate install discs, and am looking at a black screen and the little white indicator light, but have cycled through all of the recommended Mac startup key combinations, and power cord routines, to the letter, numerous times to no avail.

4. On my last attempt to restart, and after reading one post/suggestion, I unplugged the power cord from the back of the unit, and while holding the power button down, reconnected the power cord. Immediately the fan came on “at warp speed”, and the little white indicator light went out. But nothing else changed. No restart. Screen still black. I then powered down as normal to stop the fan, then turned it back on as normal, and back to square one. Black screen and little white light. Don’t know what, if anything, that signified.

5. So, if anyone can tell me what all that means, please do. In the meantime I’m almost ready to disassemble my iMac. Before I do, I am gathering cords and connectors to hook up an external monitor. If that doesn’t work, guess I will tear into it and start looking for a reset button (some post says exist), and (4) diagnostic startup LED’s (some posts say don’t exist on my model, and some posts say they do). Hopefully I’ll find a loose connection or something simple. If not, one step at a time, and start buying parts.