K5300 missing paint marking on flash tube

Hello everyone -

I have almost finished assembling a K5300 “Stroboscope” kit, but I can’t find the polarity markings on the flash tube. Is there a way to identify the polarity of the tube in the absence of the “red paint mark” mentioned in the instructions?

Thanks in advance,


If the dot is missing (has never been reported before, strange…), then you will have to determine polarity by trial and error.
Careful: Make sure unit is fully discharged before attempting to touch/desolder flash bulb!

Thanks for the quick reply. I have to ask the obvious question: polarity reversal won’t damage the tube?



Shouldn’t be a problem, however, be careful, as the caps will not be discharged if the tube has not flashed.
Leave it alone for a while and check with a multimeter if they are fully discharged before attempting to touch any part of the circuit.
There’s a 50% chance it will work right away :slight_smile:

50%? My involvement ensures it will be near-zero :slight_smile:

Thanks for the help!