Hickok 209a v.t.v.m.

[Tubejunke]

Just wondering if anyone here has one of these and/or has brought one back from the dead. I am lucky enough to have one decent shape with both the AC probe and the correct DC probe as well. That's a HUGE plus from what I hear.

Anyway, nobody has been inside the thing as far as past repair other than changing the twin D cells for resistance measurements. But the meter is frankly all out of whack. I haven't seen a function yet that it is even able to begin to take a measurement as some functions and ranges cause weird mid scale meter deflection or like the +DC function slams the meter to the left. I did find a questionable rectifier between the two that it has, but adding a better one didn't change anything.

I'm guessing that like most things that old (early 50s I think), the caps have got to go. That's probably what it will all boil down to. Luckily, there only seems to be a few caps in the unit. So maybe it won't take much to bring back what is supposed to be one of the best bench VTVMs ever made.

B.T.W., I have downloaded the user and repair .pdf files. I don't think that they have calibration instructions which I would like to get if anyone has them.

[jr_tech]

Possibly some good pointers here:
http://www.antiqueradios.com/forums/...c.php?t=126997
jr

[Tubejunke]

OK, thanks JT.

[Tubejunke]

I found out something very interesting in that link that jr_tech gave me. It seems that the D cells for the resistance functions are positively grounded. A person on that forum was having some of the same issues as I am having, being the meter slamming to the left in various functions. His was doing it supposedly in all functions. Mine only in certain ones; most particularly the +DC. It doesn't like that one at all!

Anyway, supposedly the schematic verifies the positive ground on the D cells. I was wondering why there was no indication of polarity anywhere. Heck, you would think that they would be even more inclined to indicate polarity in a reverse polarity application. I don't have the meter here with me, but I will give this a try as soon as I can and update the results. Hopefully they will be good results!

[Tubejunke]

OK, today I went in and replaced the two electrolytic condensers along with a .1 and a .05 wax/paper/foil condenser. All of them measured way off with the capacitance function of a Fluke DVOM, so I figured I would definitely see some improvement, or maybe even have a working meter. No such luck!

Absolutely nothing changed! Before I go much further I must add that I do have a questionable 6SJ7 according to my tube tester. It is a cathode follower for what that is worth. Maybe the weak tube is the whole problem. I don't yet know exactly what function it performs. No subs to try in my metal/glass goldmine.