i just finished assembling my sammichSID PCB and during voltage tests noticed, that instead 12 V i have almost 20V on every pin marked in orange in building guide. 5 V & 9 V are OK.
Is it problem, if I’m going to use 6582 & low power 5V LCD ?
Do You have any idea, what can be wrong ?
I’m going to recheck all PCB elements…
EDIT: I switched power supply from 12V DC to 9V DC, and now I have 13,4 V on every pin where should be 12V. 5V & 9V is still OK…
You are probably using an unregulated PSU - the voltage will be lower once the PSU is under higher load.
Check the voltages again once the ICs are put into the sockets, and the LCD is connected. It could be, that thereafter the 7809 won’t output 9V anymore.