My First Predicta

[Chris K]

Originally Posted by bandersen

+/-20% on the voltages is fine. They are very much dependent on your input line voltages and the operating points of all the circuits, condition of tubes etc.

Like I said, go through the resistance chart. There has to be a major smoking gun (or two) for voltages to be completely absent. It's not going to be something off be a few percent - it's going to be an open circuit or something shorted.

I've started to. First I checked all the wiring from the AC line to the line filter cap, through the diodes, through the choke and the electrolytic caps that bracket it. It all checks out so that means I didn't screw up those first 3 electrolytics.

I started with V1, first tube in the chart and the first video IF tube, a 3BZ6. Pin one should be 1.5Mohm and I have that. Pin 2 should be 47 ohm and I have 65 ohm. Pin 3 should be 14 ohm and I have zero. Pin 4 should be 15 ohm and I have zero. Pin 5 should be 330 ohms measured from the 140v source and I have 420 ohm. Pin 6 is the same measurement parameters as 5 and I have the same 420 ohm. Pin 7 to ground should be zero and I have 0.1 ohm. Looking at the schematic, I don't see pins 3 and 4 connected to anything so I don't know what these mean. I really apologize asking you to take me by the hand but is there a tube in a different section I should check that would help figure this out faster?

Thanks Bob