I retested the Emerson 637 set, which appeared to show too few cycles for a known-good flyback when I tested yesterday (and posted on page 2). This time I really had all connections removed, and it looks decent.
I think previously I had noticed that removing the 1B3 in that set had only a minor impact on the ringdown and then plugged it back in. However, after removing all other connections, it may have been having a bigger effect, being the only remaining load. So the previous picture with "no yoke" still had the 1B3 filament load. Got to be careful to make sure all connections are removed for a final test of a flyback.
So I think that removes all doubt about this particular method for testing flybacks. If you get something like 10 decent cycles of ringing or more, the flyback is OK. If you don't, it has high loss (low Q) from a shorted turn.
Looks like this will be a good technique for checking flybacks going forward.
|