Testing circuits?

[deletemeplease]

Can anybody explain to me roughly how to test circuits?

I'm able to follow the instructions TK gave on ucapps.de but my core doesnt work and it would be interesting to learn how to test the circuit properly.

At the moment all i use my multimeter for is continuity checks, which doesn't really tell me an awful lot about the circuit!  ::)

I read this site http://www.doctronics.co.uk/meter.htm which told me a little about using the multimeter's functions (and i also got the resistor colour code converter - which helps you work out what resistor you have in your hands).

Any tips would help!

Thanks! Paul

[pilo]

huumm to test circuit, and this kind of "digital" circuit, you need an oscilloscope and a logic analyser... to see what appen with the clock, and all logic signal.

To see if the core works, if you use MIOS (pic 18f), with midiox, you can see if you receive the "ready to send" syx message...

I think that if you follow TK instruction, and it still doesn't work, maybe the error is somewhere else.

I think a good test program would be pull to high level all pin of the pic, so we can be sure that the pic is working... maybe a quartz problem...