Thanks Phil, yes it has been suggested in this thread that the 1N34 is what I would need as a replacement for the crystal detector diode that is open (along with a coil that is in series with it) in this set that has now been sitting in stumped mode for a few years. I still battle almost no vertical sweep, but I now have an oscilloscope to help along with some formal training in signal tracing on my side. Before I was limited to the use of a DVOM and a tube tester. I have several tube testers by Hickok, one of which is a mutual conductance job from the late 40s. Unfortunately, the setup data on that one doesn't cover a LOT of tubes including several in this late 50s Zenith. From my studies of tube type television circuits I see that the vertical sweep section is probably the most simple circuit in the average set, minus the low voltage power supply I guess. Thanks agian partner! You always seem to be there with plenty of helpful information!