GFDuke,
Maximum resistance of a 500Ω VR is 500Ω, depending on the resistance measurement setting on a multimeter 500Ω can appear as "0.500" (0.5kΩ).

Wile E,
You mean this card? Is the square chip a RT8802A?

If it is RT8802A:
Measure resistance from pin#17 to ground, solder a VR 20× measured value from that pin to ground. Tune down to lower OCP trigger point.