Why won’t my Von Duprin 6100 or 6200 series electric strike lock and unlock properly?

Electrical checks

• A regulated filtered DC power supply is best power choice.
• If AC is being furnished, an SO rectifier kit is required between the power source and the strike. It will not work properly with AC.
• Solenoids with black wires require 24VDC. Are you reading 24VDC (+/- 10%) under load at the connector near the solenoid?
• Solenoids with yellow wires require 12VDC. Are you reading 12VDC (+/- 10%) under load at the connector near the solenoid?
• Check solenoid resistance:  24VDC - 82 OHMS; 12VDC – 21 OHMS

Mechanical checks

• Is there pre-load against the strike lip (keeper) when the strike is installed? There should be 1/32” clearance between lip and latch. If the latch is pressing against the lip when the strike energizes or deenergizes, the internal slider can’t move because an internal protrusion from the strike lip pushes against the slider.
• Take the strike out of door or frame to eliminate pre-load and to check for issues or excessive heat. 
• If the strike is operating oppositely from what you are expecting, you likely have the wrong fail mode of strike (fail safe instead of fail secure, or vice versa). The strike can be converted between fail safe and fail secure by ordering a part shown in these instructions.
• Does the strike work in one orientation, but not when you turn it upside down? Unscrew the solenoid. Verify that the spring and white washer are inside the solenoid and that the plunger moves freely. 
• Are the strike lip spring and the slider properly installed? Reference the slider conversion instructions.

Do you have other electric strikes working nearby such that you can swap solenoid or power source/wiring? See if the problem follows if you move the strike to another opening.