Zenith yoke woes...

[nasadowsk]

Ok, I'm diving into my 24H20 chassis set, and, I can't get any good sweep/HV out of it. With the yoke connected, I get zero HV and some decent loading of the flyback. If I disconnect the yoke, I get some HV (7kv or so), and the fly seems happier. I'm not sure what else it could be but a bad yoke at this point. Any ideas, or do I need to start hunting one down? See attached schematic snippet, below.

thanks guys!