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?
There is a problem with the temperature circuit.
Are you sure?
I’ve reconnected a few time this circuit and the problem was still the same.
The osscillator is broken?
The microcontroller turns off the display if the information that comes from the temp. circuit is incorrect or missing.
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?
We have the impression that you are not assembling the original kit.
I’m sure you’ll understand that we cannot support copies of our products.
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?