Niel MalanI though that the problem might be simply that some deposition had formed between an incoming and outgoing conductor, causing a short circuit or a leak. In that case all that might be needed would be a simple cleaning.
I don't think it's going to be that simple. As far as I can tell all the traces are printed on, which means, I think, that it is the interleaved layer of insulation that is failing.
Discussions
Become a Hackaday.io Member
Create an account to leave a comment. Already have an account? Log In.
Yes, I have disconnected the keypad from the control circuitry. This was my first indication that it was the keypad that was the problem: on power-on the screen does not give its usual test pattern, but acts like a button was pressed. If the keypad is unplugged, the normal test pattern appears.
Are you sure? yes | no
Have you disconnected the keypad from the control circuitry? If not, this sounds to me more like a problem with the IC that is scanning the key matrix (an internal short). If you can disconnect the keypad, then check continuity, you can establish if it's actually a circuit board problem or a chip problem.
Are you sure? yes | no