Cant recognise a Damaged component of switched-mode power supply

I was repairing an smps ATX power supply I found a damaged component that I could not it recognise. I thought it's a power switch since it was mounted to a heat sink along with tow D13007 NPN power transistors and I could not find the datasheet due to the missing part number after explosion .Can someone with expertise in this type of circuits guess what this could be?

Is it true tho?

Tried putting 866S into a couple of data sheet search engines as "included" rather than "Match" but nothing suitable came out.  This might be a MOSFET or it might be a dual rectifier, these are common in power supplies.  If you can trace the tracks and see where they go it might help. If two leads go to transformer windings and one goes to a capacitor it would be a dual diode.  If one lead goes to a transformer winding, one to ground or a power line, and one to somewhere that is obviously neither, it would probably be a FET.  The component markings on things like this are not always recognisable even if you have the whole number, so you need lots of luck and good detective skills...

HiDo you know the manufacturer of the board or are there any markings on it that may help identify the board and from a schematic the component?Regards

Actually I found the missing piece of the damaged component it turns out that it was a  power NPN bjt  with part number 3866s. Anyways thank you for your help.