Hello again Dave. I think I understand what you are saying about single LEDs. Looking again at the ones I have, they have in fact got three small leds per beam. I think I was originally comparing my current lamps to the earlier awful ones that are composed of many leds- which are beyond pointless! But, thinking about the mot tester, could it be, given the fail description, that the lamps were rejected even before a beam test? Either way, I'll put the filaments back in before the next test...
Next time I'm spending, I'll be more careful!
And that 555 'scope looked nice. Elegant design! I went off on a wander, looking again if a microcontroller (raspberry or arduino) could come in to my life. But too much work, it turns out. On a simpler note, I found 'use your smartphone as a scope' eg:
https://www.instructables.com/id/A-P...Oscilloscopes/
Which would suit me fine- as I have a few old phones...
But best of luck with the main project in the other thread (and luck to Andtwenty too)- it will be fascinating to hear of the end story!