From what I remember, the 6802 is an old micro-processor, as such it requires an external clock, external RAM and ROM, and external interface components. What you can check is highly dependent on all those.
For a start I would use a scope to make sure you have a clock input, and to check for high speed data on the data and address busses. I would also check that the reset circuitry is working correctly.
Micro-processors are usually very reliable, particularly an old one like this (where anything nasty is connected via an external chip), it's not very likely to be faulty.
There are only two real ways of testing it - either try a known working one in it's place, or try this one in a known working application.
The problem with any micro design is you don't get many static voltages, the +ve supply to the chip and the reset pin are about the only ones. Every thing else is likely to be switching high and low at varying speeds.
A scope doesn't help a great deal either, basically it can only show high, low, or varying data - not what the actual data is. A logic analyser is often used to help you see what's going on.
As regards scopes, you are far better with a proper scope, rather than a PC software one - although a PC software one will usually work as a fairly low spec storage scope, which might be useful.
Micro-processor systems are generally hard to fault find, what is the problem with this one?.
The most common faults are generally with sensors and external interfaces, micro-processors them selves are usually very reliable.
Nigel,
I"ve had a sqizz, (look ) at ya ,(your) sites, . and realized I might be barking up the wrong tree, i'm new to this kind of electronics and have lots more learning to doo
Thanks for ya help so far (thanks for your replies)