Troubleshooting | Focus Technologies LLC



The MK 3 requires a minimum of 12 volts to function properly.

1. Plug in the power cable in the back of the MK 3, if a red LED appears, there is power to the unit. If not, use the backup cable; if the red LED fails to turn on check to see if the camera battery has sufficient charge. If its low, change the battery and this should resolve the problem.

2. If the display turns off, change the 9v in the back of the display. If it is intermittent, the contacts for the 9v need to be bent out a little to ensure proper contact to the 9v.

3. If the display is dropped, or banged hard, there is a safety feature built in to turn it off. Press the power button and this should solve the issue.

4. If during the day your display starts showing erratic numbers or behaving out of the norm, it probably signifies that the camera battery is getting too low for the MK 3 to function properly; change the camera battery and this should correct the issue.


1. The display is reading erratic numbers and wont stabilize.
A. If the power protocols were gone through and didn’t correct the issue, then the most likely answer is that it’s getting interference from the Preston or the HD transmitter on set nearby. The only correction is to change channels on either the Preston or the HD unit.


1. The targeting laser is getting dim or progressively dimmer.
A. The only way for the targeting laser to start dimming, if the unit is less than two years old, is for the unit to be under driven. This means that the unit has been getting less than 12v for an extended period of time or frequently. The only fix is to send the unit in and have the targeting laser replaced and adjust the camera battery management to change out the camera battery before it hits 13 volts.

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