Remove the cooling fan and replace it with a new fan of equal size and type: 60 x 60 x 15 mm, 12V DC. Carefully compare for fitment.

Solder the wires together and apply appropriate insulation. Red to red (+), black to black (-) Shrink wrap works well.

If needed and possible, ensure that the fan blows in the same direction, out of the over box through the little fan slots. Check this when the unit is turned back on.

A good replacement candidate of the fan can be bought from www.digikey.com. Part number 259-1802-ND. It is a Sunon fan of higher quality than the Hongfei HD-6015L12R fan that is replaced. This fan is confirmed to blow air into the same direction as the old fan.

Insert the new Sunon fan with the label facing into the control electronics compartment. The wires need to exit the fan housing on the top when inserted. Dress the wires to ensure that they do not touch the (hot) metal housing or heatsink. Use tie wraps if needed.