I think Ron and Lee's suggestion is the answer. I tweaked the needle ever so slightly where the needle takes a 90 degree bend. I was able to put it dead nuts on. The needle looks straight as a pin. Now that I think of it I had a catastrophic 6JB6 failure some time ago which most likely caused the needle to slam hard against the stop which may have caused the needle to bend. I'm not sure why I didn't notice the problem then because I had to replace the finals, both screen resistors, and the meter shunt, reset the bias and re-neutralize the finals. It was nice to have Garey's CD, I was able to go right to R36 the 2.7 ohm resistor. THANKS TO ALL WHO RESPONDED, A GREAT GROUP! John Meyer K8IHY > Date: Mon, 14 Mar 2011 09:28:50 -0400 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [Drakelist] T-4XB Meter > > John - > > Never seen a meter built that way!! :-) > > The coil at the bottom of the needle is a counter-balance adjusted so > the pointer is steady in all orientations of the meter. > > I'm seeing the flat 'bar' behind the rear disc that looks like it might > slide between the two rivets holding it to the back shell. Can that bar > be moved up and to the right?? Garey,Not that I can see. It looks like it's > unmovable. > > The coil (assembly?) itself looks like it too is tilted toward the left.? > > By the way, Drake paid slightly less than a dollar for these > meters........ !!Yes it looks el-cheapo. > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line > and TR-4/C Service Supplement CDs > <www.k4oah.com> > > > John Meyer wrote: > > Ron and Garey, > > > > I tried taking a couple pictures of the insides of the meter. My > > picture taking skills are lacking as is my camera. Hopefully you guys > > will be able to open the attachments and get some kind of idea what it > > looks like. On the bottom of the needle is a curled up brass stub that > > appears to be a counter balance. Also there are two small round disc > > on the main shaft. One rides inside the coil and one outside. These > > disc look like a PM. There is no spring. I have a hunch that the > > positions of these PM disc is what determines the resting position. > > > > John Meyer K8IHY > > > > > Date: Sun, 13 Mar 2011 16:25:39 -0700 > > > From: [email protected] > > > To: [email protected]; [email protected] > > > Subject: Re: [Drakelist] T-4XB Meter > > > > > > Garey, > > > It has been over 10 years now, but I really don't remember seeing > > any springs. I figured that somewhere there was a stationary magnet > > that "held" the meter movement. > > > > > > John has his open from the way it sounds. So hopefully he can tell > > us what is inside. > > > > > > 73, > > > Ron > > > > > > --- On Sun, 3/13/11, Garey Barrell <[email protected]> wrote: > > > > > > > From: Garey Barrell <[email protected]> > > > > Subject: Re: [Drakelist] T-4XB Meter > > > > To: "Ron" <[email protected]> > > > > Date: Sunday, March 13, 2011, 5:43 PM > > > > John - > > > > > > > > Ron is one up on me, I've never opened a Drake meter and > > > > did not realize they were 'moving vane' types rather than > > > > moving coil. Generally, moving vane meters are not > > > > adjustable for zero unless the suspension can be > > > > rotated. There must be some sort of 'return spring' > > > > rather than gravity to make the meter come to rest at the > > > > zero point. You might be able to spot it by blowing > > > > air GENTLY to move the needle up scale and see what brings > > > > it back. > > > > > > > > 73, Garey - K4OAH > > > > Glen Allen, VA > > > > > > > > Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line > > > > and TR-4/C Service Supplement CDs > > > > <www.k4oah.com> > > > > > > > > > > > > Ron wrote: > > > > > John, > > > > > Not sure that degaussing would be what you want. > > > > My guess is that the north/south permanent magnet is on that > > > > disk. Then the coil causes a magnetic field that moves > > > > the disc and the pointer with it. > > > > > > > > > > Every analog meter I know has a permanent magnet > > > > somewhere and a coil to create a deflection relative to the > > > > permanent magnetic field. The Drake meters are > > > > "backwards". Most meters have a moving coil > > > > and stationary magnet. Drake has a moving > > > > magnet and stationary coil. > > > > > > > > > > I believe that is you degauss the disc, the meter will > > > > never work again. Thought anyone else? > > > > > > > > > > 73, > > > > > Ron WD8SBB > > > > > > > > > > --- On *Sun, 3/13/11, John Meyer /<[email protected]>/* > > > > wrote: > > > > > > > > > > > > > > > From: John Meyer <[email protected]> > > > > > Subject: RE: [Drakelist] T-4XB > > > > Meter > > > > > To: [email protected], > > > > [email protected] > > > > > Date: Sunday, March 13, 2011, > > > > 1:58 PM > > > > > > > > > > Ron, > > > > > > > > > > Thanks for your input. I'm a > > > > little afraid to try bending > > > > > the needle. It's going to take > > > > a steady hand. I wonder if the > > > > > problem develops because of > > > > some residual or stray magnetism. If > > > > > that were the case possibly a > > > > degaussing device like used to > > > > > demagnetize tape heads would > > > > resolve the problem. I believe I have > > > > > one of those devices around > > > > here some place left over from my days > > > > > of servicing tape decks. > > > > > If I can dig it up it may be > > > > worth a try. > > > > > > > > > > > ------------------------------------------------------------------------ > > > > > Date: Sun, 13 Mar 2011 > > > > 06:24:15 -0700 > > > > > From: [email protected] > > > > > Subject: Re: [Drakelist] T-4XB > > > > Meter > > > > > To: [email protected]; > > > > [email protected] > > > > > > > > > > John, > > > > > I have a meter here too that > > > > is the same way. It appears that the > > > > > meter movement is made of a > > > > disc of magnetized? material inside of > > > > > a coil. I was going to > > > > carefully bend the needle, but I happened > > > > > upon "new" one. It's > > > > been some time, but I was going to approach > > > > > as follows. Put a close > > > > fitting brass tube from the model > > > > > airplane shop over most of the > > > > needle. With a very fine pointed > > > > > pliers hold the base of the > > > > needle (above the movement bearing > > > > > area). Now very slowly > > > > bend the needle in the direction needed. > > > > > > > > > > BTW this was the meter that > > > > left me with a small piece of plastic > > > > > in my cornea. Just had > > > > my eyes exam this week, and doc tells me I > > > > > am a very lucky. > > > > > > > > > > 73, > > > > > Ron WD8SBB > > > > > > > > > > --- On *Sat, 3/12/11, John > > > > Meyer /<[email protected]>/* > > > > wrote: > > > > > > > > > > > > > > > From: John Meyer > > > > <[email protected]> > > > > > Subject: > > > > [Drakelist] T-4XB Meter > > > > > To: [email protected] > > > > > Date: Saturday, > > > > March 12, 2011, 1:37 PM > > > > > > > > > > My T-4XB meter > > > > movement is off scale to the left of the zero > > > > > mark. I have > > > > removed the meter and to my surprise there > > > > > doesn't appear > > > > to be anyway to zero the needle. Any suggestion > > > > > to get the > > > > needle to rest at zero would be appreciated. > > > > > > > > > > Thanks, > > > > > > > > > > John Meyer > > > > K8IHY > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > Drakelist mailing list > > > [email protected] > > > http://mailman.zerobeat.net/mailman/listinfo/drakelist
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