18-08-2012, 03:49 PM
OK, I admit defeat, or at least confusion.
I've been fiddling about with this for the last few days and have discovered that if I connect my 'scope to the rail indicated by the arrow below there's not only a waveform but the thing works. As soon as the probe is taken away it shuts up again. It doesn't matter exactly where it's connected so it isn't that touching a particular component and temporarily making a dry joint conduct.
I did wonder about the health of the second transistor, the only one shown on the above snippet, but changing it has made no odds and the original tests good.
Any ideas as to what I should investigate next? Like blanket cap changes it would have been far quicker and easier to just make another but not as satisfying.
Cheers
Joe
I've been fiddling about with this for the last few days and have discovered that if I connect my 'scope to the rail indicated by the arrow below there's not only a waveform but the thing works. As soon as the probe is taken away it shuts up again. It doesn't matter exactly where it's connected so it isn't that touching a particular component and temporarily making a dry joint conduct.
I did wonder about the health of the second transistor, the only one shown on the above snippet, but changing it has made no odds and the original tests good.
Any ideas as to what I should investigate next? Like blanket cap changes it would have been far quicker and easier to just make another but not as satisfying.
Cheers
Joe
