HICKOK 209A HUGE dial VTVM calibration data/help needed.

[Tubejunke]

I have been trying to get this Hickok 209A Volt, Ohm, Cap, Milliampere tester going. This is the one with the BIG meter. I think it was the biggest ever made & what little info. I see on the WWW says among the best ever made.

I hope I can get some calibration instructions on this and some repair tips. I have the user manual and schematic, but it doesn't go into calibration. There is more wrong than that. The +DC range will slam the meter below zero, so I have to stay away from that. -DC is not so bad, but won't go to zero. I have replaced almost, if not all the caps; cleaned switches and pots, and found one bad tube. I guess next I will look into resistors out of tolerance.

The manual sort of gives you a rundown on checking the meter before use and really none of the results I get are what they should be. I think the mA function is right. There is a thread on Antique Radio Forums on this topic, but they say that there are two calibration pots when there are actually four. Not sure what is going on there. I have submitted a password and will likely paste much of this to that topic forum.

[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...

[jr_tech]

The peak to peak reading sounds about right... remember 30 V rms times 1.414 gives you the peak value... times 2 gives you the total peak to peak:
30x1.414x2= 84.8volts p-p

jr

[earlyfilm]

I don't mean to hijack your thread, but I have an earlier 209A, made when the normally silver parts of the case and dial were black.

It is very similar to this one on Radiola Guy's website:

http://www.radiolaguy.com/images/equ...kok_209A-e.jpg

I'm never started rebuilding mine, as I cannot figure out how to get the AC probe apart to check the 6AL5 and the associated circuitry.

Unlike the later silver ones, and Radiola Guy's picture, my probe is all black and looks like it is cemented together. Any ideas?

James

[Tubejunke]

My AC probe is a silver sleeve with two black caps for ends. It is taken apart by removing a number of small set screws. I have seen the black face versions of these and I like the look. I'm not sure what years they did that or why. I am fairly certain that the 209A was introduced just after WW2 and ran unchanged up until the similar 209B came about in the 60s.

Supposedly we own just about the best VTVM ever made from a few comments I have read by owners or ex owners who wish they still were owners. I absolutely love mine. I did before it was working, which gave me the determination to get it working. The equipment of that era just had a certain appeal that's hard to explain.

[Tubejunke]

This rather problem ridden beauty I described turned out to be a simple matter. There are about 4 tubes in these things as opposed to 2 in most any VTVM. One of them that controls the bridge is a 6SN7 and I found out that both sections of the dual triode must be close to the same when tested. The tube I had under most any other application would be fine, but it wasn't balanced. I found one that was close and all of those troubles I mentioned went away.

Then you get to calibrate which is a bit tricky, but well worth the effort. I like the thing so well that I purchased a 203 (I think) on Epray. It is a lot smaller and doesn't bear the super cool huge meter, but the price wasn't bad and the thing has supposedly been checked out and functions as is, so maybe no project like much of the stuff I've gotten there. It's too easy to see these neat looking pieces of test equipment and throw out a bid. Not so neat sometimes when you get them; or you realize that you really don't need them. If it says Hickok on it, I am apt to want it. I love their vintage equipment. They are to test equipment what DuMont was to television!