R39 is a the low end half (grounded half) of a voltage divider, in a voltage sense circuit.

When the DAC Module power plug is shifted one pin to the left during installation (Thanx Bill Thompson) R39 releases its smoke.

R39 is a 1/8W, 10Ω Flame Proof, Metal FIlm; However, A 1/4 Watt will fit through the PCB pad holes.