Question about testing flyback

[Aperna1985]

I have a 1951 RCA television that I can't get to produce more than 5kv of high voltage. The other day I was testing for voltages and the 6BG6 was reading low voltage or no voltage on a lot of terminals. Then I accidentally knocked the wire off the focus knob as soon as I did that I got all my voltages back. And they were close to what was specified in the Sam's. The focus wire I knocked off comes from the flyback Transformer, and connects to the focus control and then to the picture tube. I tried metering the fly back and the resistance ratings were within two or three ohms of what Sams said. Is that a reliable enough test? Or should I buy a flyback tester of some kind