I found a boxed A500 setup

[mr_a500]

The A500 has a red power light which for some reason seems to be older and more original than the ones with the green power lights to me. I have no idea why some have read power lights and some have green ones.

I've never seen an A500 with green power lights. I didn't even know they existed until somebody mentioned it in a forum.

From what I've seen (& in old computer magazines), it looks like sometime in the late 1980's, indicators in electronics went from "red=on" to "green=on" and "red=problem". All my pre-90's computer stuff has red power LEDs and all my post-90's stuff has green power LEDs.

[mr_a500]

Commodore went from red to green power led's in their A2000 when the Rev 6 A2000 was introduced. Same happened with the A500. Red power led usually means you have a rare rev 3 (the one with the C= left key instead om Amiga key) or a rev 5. Rev 6a machines usually have a green power led. All (original) rev 8A (500's and 500+'s) all have a green power led.

Thanks for the detail. Both the A2000 Rev 6 and A500 Rev 6a appear to have been made after WB 2.0 was released, so that means they're both made after (or in) 1990. That makes it easy - if you've got a green power LED, you've got a 90's Amiga.

I think it also has to do with cost. Green LEDs didn't really get made in volume until the mid-80's and they were probably more expensive. By around 1988/89 they probably came down in price and that's when manufacturers started switching.

Of the 25 80's/early 90's computers I own, only the Apple IIc doesn't follow the pattern. It and its matching monitor have green power LEDs and they were made 84/85.