On 1 September 2015 at 10:59, tony duell <a...@p850ug1.demon.co.uk> wrote: > > > What do you see on the collector of TR23, which should be a small power > transitor (TO220 package I think). If it's working properly there would be > some > very high voltage spikes (kV) there, but under these conditions probably not. > What > is the average DC voltage there?
Hmm, you are right, I am not seeing any spikes in voltage there. On the collector of the TR23 all I am getting as DC voltage is around 110mV. The oscilloscope tells me I am getting Vpp of about 4.4V with Vmax at 2.6V and Vmin at -1.8V and an average of 105mV (which matches what my multimeter tells me too). That sounds too low doesn't it? > > Could be, You have a schematic, the flyback windings should be very > low resistances. Check them with the ohmmeter. > I did measure the resistances across pins of the flyback transformer on the same windings and I am getting (what I think are) good results: 1 or 2.2 Ohms (for the 2 windings left and right, not the upper one, as I do not want to touch the high voltage stuff for now). > -tony
