[Tubejunke]

OK, not much going on here, but there are a few tidbits out there on the WWW if you look REAL hard. These meters are HIGHLY heralded, but were very expensive when new which may dictate there scarcity today. Loved by all who have or had them and regretted actions by sellers. Anyway, I made some ground tonight with this meter and I want to bring the info to this site which is my primary and favorite site.

So I opened it up again and checked the 6SN7 on my B&K Dynajet 747B and found marginal emissions or micromhos on one side and about 10% higher and barely in the "green" on the other. The information I gathered told me that the 6SN7 was very critical as far as balance within the tube and thus the bridge circuit. Anything short gives problems such as I described previously. I was able to come up with a Tung-Sol that wasn't great on the numbers but balanced identically. Then I switched the D cells to positive ground. There are no polarity indication marks inside the unit, so I had the cells in there the way my VOM told me they should be under normal circumstances. Not so normal for whatever reason in the 209A.

NOW I am absolutely amazed! Most all problems just vanished and I'm talking without even attempting to set any of the 4 calibration pots which I am sure I have WAY out of whack from cleaning. I marked position, but the cleaning process took that away. No big deal as most of the measurements I have taken are reasonably close if not spot on. I question the peak to peak readings. I had it connected to a 30 VAC source and read about that in NORM, but PP shows about 90VPP. That's not a function that I don't expect to be using much, but I want it all to work.

The cap test works, but I only tried a .1 and frankly I have to get used to the scale along with multipliers and divider selections. I got a .95 on the X1 scale. The other scales are "iffy" to me.

I have been periodically messing with this thing forever it seems and nothing seemed to be helping. At least there are new caps in it now, but my money says that it was mostly that 6SN7 as all symptoms were the same from the get go. The caps were probably OK. I just tacked in most so when I get my Heathkit C3 tuning eye cap checker going (CAPS-geez) I will run leakage tests on the caps that I left in place and may reconnect a couple of them like the meter dampening cap for one. I know that is crazy to many, but I among the crowd that doesn't like replacing caps that work for the sake of originality. My favorite TV sets and radios are those still working great with mostly original components. To each their own; right?

When I get time to tweak the calibration pots I will post results. If anyone at all here has one of these, please chime in and tell me how yours works, repairs etc...