Quote:
Originally Posted by Vintage Engr
... Unbelievably, the output transformer is o/c on one of the secondary windings!
I'm wondering if perhaps the wire was never soldered to its relevant tag.
But how did it pass a final test? ...
|
Sorry if this is teaching my granny to suck eggs, but are you certain ? The secondary turrets on the 'normal' i.e. 8ohm/15ohm transformer are P, Q, R, S, and T. But there are actually two completely separate windings - one goes between P and S with Q as a tapping, the other goes between R and T. So if you try to measure each 'section' from P all the way to T you'll find a break between R and S. This is how it's meant to be. PQ is the negative feedback section. For 8ohm speakers QS and RT have to be connected, with jumper wires, in parallel. For 15ohm ones they have to be connected, with one jumper, in series.
Cheers,
GJ