Dell Optiplex 7060 MFF Faulty Motherboard

I have a Dell Optiplex 7060 MFF that wont boot, according to the power LED flash sequence it has a faulty motherboard.

The motherboard has a model number of IPCFL-BS 65W.

It had a decent i7 processor so I removed it and put it in a lower spec 7060 that I bought, I then installed the i5 from the other 7060 but it still wouldn't boot, no surprise there!!

I suppose I can do one of the following:

• sell it as is for spares or repairs on eBay (the CPU (i5-8500T) has got to be worth at least £30 on it's own)
• get a replacement MB from eBay or an AliExpress clone
• try and work out what has failed on this MB and fix it (this is way above my skill level)

Anyone have any other ideas or suggestions?