Hello all. I am repairing a Nikon SB-80DX flash and I do not have the benefit of a schematic so I was hoping someone could share their thoughts on my findings. I think I have narrowed the problem down to a faulty transistor. Please see
When I fire the flash I get a voltage pulse at location 1 in the photo pulse is of correct amplitude and duration. Location 2 at the transistor is connected to the one side of the capacitor shown, the voltage here is 285Vdc. Location 3 at the other side of the capacitor is connected to the purple wire that is connected in the flash head to the primary side of the trigger coil.
Am I correct in assuming the pulse at location 1 of the transistor should be amplified and show up at location 2 allowing 285Vdc to briefly pass through the capacitor to the purple wire located at position 3 which in turn will be stepped up by the trigger transformer and trigger the flash?
When fire the flash I do not get any voltage at the primary of the trigger coil but I do get a pulse at location 1 in the photo.
I am not looking for a definitive answer of any kind just an opinion on the validity of my findings.
Sincerely, Donald W. Doucette