Have had a bit of a play around with the engine diagnostic machine today. Have changed a few duff lamps and given it a bit of a clean. It seems the longer it's been powered on the more things are coming back to life. Laziest thing seems to be the analogue meter, though that's working reasonably well now - the signal for it follows a torturous route through a heap of switch contacts so they are most likely to blame.
Scope part seems to work just fine though - especially once I realised that you *must* have the coil SW and CB terminals connected for it to do anything (including showing the alternator charging waveform) as it triggers on the pulse from there. Would be nice if the manuals had information like that in them...as it wasted me about half an hour...
Here's some of the stuff it can do...
Skoda's ignition system trace - it's really hard to get a photo of the scope output as it is effectively drawn in realtime so the scan rate is very slow as far as a camera is concerned. My camera does have a "light painting" mode which in conjunction with a tripod might get me a good shot...

Here we have the charging waveform at the battery, showing that all the windings are working as are the rectifiers. Right hand end of the trace has been cut off by the camera...

Finally some more basic stuff - battery voltage and a pretty precise RPM readout (which is shown on the digital display in some modes too).

Took me a while to get used to keeping track of the fact that it jumps between scales to give the best possible resolution! Especially as several of the lamps illuminating the arrows were blown when I got it.
Fun toy that's for certain, need to set about giving it a proper clean up soon as it's still kinda gross in places!






