Power Module with AC & DC Input

[alec_t]

When using a bridge rectifier with a 110VDC input, bear in mind that two of the diodes of the bridge will conduct continuously (instead of in alternate half cycles as when using AC), so the bridge average/RMS power rating should be chosen accordingly.

 

[4pyros]

What we really need is a schematic of the existing power module, without that we're just blindly guessing.

Yes the OP still has not given us the specs for the model.

 

[ronsimpson]

Several options.
1) Use a transformer to drop the 110ac to 75vac so the rectifier + capacitor will give 110dc. This will work BUT you will have two inputs. DC or AC Putting DC on the transformer will not end well.
2) Use a linear regulator to drop 150v to 110v at 0.5A will result in 20 watts of hear being wasted. We can make a simple circuit the will take 110dc and make 108dc and any voltage above 112 (ac or dc) will be dropped to 110dc.
3) Use a PWM to do the same as #2 but with 2 watts of loss.