As far as I recall, there is no adjustment. Typically the display area can be cleaned as smoke and dust collects on the plate. Remove the front panel and clean the inner surface of the plate. You may find that sufficient to resolve the problem. If not, then check the power supply for 5V and 12V. If the supply is low, the unit will still work properly, but the display can be dim.
Answers & Comments
As far as I recall, there is no adjustment. Typically the display area can be cleaned as smoke and dust collects on the plate. Remove the front panel and clean the inner surface of the plate. You may find that sufficient to resolve the problem. If not, then check the power supply for 5V and 12V. If the supply is low, the unit will still work properly, but the display can be dim.
Dan