I am building the K8009 with displays an a new PCB.
I have this problem: when i connect the power, the displays are normall (hours lights on and off, the other displays are zero). I can change this with the buttons, but after a few seconds, all the displays are off.
I only use the time calibration, the CD ic and the pic ic with transistors the same as in the schemtics.
Does anyone know this problem?
Is there a bad connection or an other problem?
I’ve test it and when i connect nothing on pin 16 and 15 of the microcontroller, the displays still work but the seconds are not correct and the displays are bad to see. After a longer time, the displays will be off.
I measure also a frequency on pin 5 of the pic, which is tunable with the trimcondensator.
Maybe it’s because I don’t use the temp schematic, and left pin 2 of the pic open.
Do I need to connect this pin to +5V or to ground or left the connection open?
I do assmeble the Velleman kit, but I only need to display the time, so I use only the components I need.
Is the temp calibration necessary for a good working from the PIc without you need to display the temp?