Chosen Solution

Few questions on the speakers:

  1. What is the pin out for the four wires from each of the built-in speakers connecting to the logic board?
  2. Where is the 17 watts amplifier powering the speakers, is it on the logic board or contained in the speaker units? In other words, can I hook up those speakers to an external source and have audio play through them at native volume levels?

here is the PINOUT for the Speaker Connectors on Logic board 820-2828 Update (06/21/2020)

here is picture Update (06/21/2020) Dear friend, Thank you very much for your great news. About speaker, sorry that it can not support the original iMAC speakers . As it can not provide enough power. But it can support the 5W 8ohm speaker instead. Will this give you the answer? Hope you enjoy shopping with us all the time. Have a great day!

Searching for “K62 mlb” on google gives the iMac 27" main logic board’s schematic diagrams. Finding any pinout from that is pretty straightforward.

I bought these 8 ohm/5W speakers on ebay, since the seller of the LCD controller board said they would work. I plugged in and they did NOT work. I checked the pinout and then swapped the black and read wires and plugged in and they did NOT work. http://www.vslcd.com/Specification/M.NT6… https://www.ebay.com/itm/1-Pair-8-ohms-5…