Re: Shack clock contrast adjustment


KI7MWA
 

Hey, Ken!  In the file www.qrp-labs.com/images/clockkit/clock_assembly3.pdf , at the top of page 6, under the heading "LCD Contrast Adjustment" is the following text (along with an illustration of the position of R4 on the Clock circuit board): "Resistor R4 is an optional resistor, which is in series with the top of the contrast adjustment potentiometer R1 and +5V. Typically the contrast voltage required is less than 1V and the adjustment is rather sensitive. If you wish, you can fit a 220K resistor in this position, which will make the contrast potentiometer less sensitive to adjust. Install one of the two choices: a) A 220K resistor at R4 (this resistor is not supplied in the kit, OR b) A jumper wire in the position shown, and NO R4."

Join QRPLabs@groups.io to automatically receive all group messages.