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
