My crazy 19VLTP22 Amplifone tube experiment

A few weeks ago, I mentioned that I ordered a 19VLTP22 tube as a
replacement for the Amplifone tube. It arrived a little while ago, and
last weekend, I had a few moments to experiment with it.

I transplanted the yoke and magnetic rings from the old Amplifone tube
onto this new tube. Just for grins, and not knowing much better, I
figured that I'd try to align the yoke and rings just as they had been
on the previous tube. (I can hear the laughter..) I know that I was
dreaming, but I figured that maybe, just maybe, it might be close.

Once everything had been grafted, I turned the beast on, and of course
it did not work. :-0 !!! The over voltage LED lit, and gave me a good
scare. I thought I blew up my Amplifone boards because I saw a puff of
smoke come off the deflection board! "Umm.. what just happened here??"
So, I decided to see if I blew up these pieces or not, and I grafted the
parts back to the original tube, hooked everything up, and it worked
fine. So, I didn't destroy anything in the process. Then I noticed
what I had done wrong previously! When grafting the DAG wire from the
old tube to the new tube, I lost some of the length of the spring, and
the wire had a shorter reach. When I put the monitor in the game, I
couldn't make the DAG wire mate with the harness, so I got clever and
decided that I'd use a jumper wire to jumper them together. Well, in my
haste, I neglected to see that even though the DAG wire is 1 wire, that
it actually connects to 2 wires on the other side, and they get jumpered
together on the tube side of things. I missed this detail, and only
jumpered the DAG to one of the wires, leaving the other one unconnected.

Aha! With the old tube in place, I unplugged the DAG wire to see if I
could create the same atmosphere. Everything flipped out as before.
Hypothesis confirmed. Dought! So, I swapped the components one last
time to the new tube, made sure to connect the DAG wire correctly this
time, and everything worked nicely.

I spent a few moments fooling with the purity and convergence, and
managed a picture that was reasonable. It's not perfect by any stretch
of the imagination, but it looks pretty good.

The resolution of the tube was not as good as the original Rauland
tube. I don't know why these tubes cross the to exact same part if they
aren't really identical. Anyway, it was a sucessful experiment. So, if
any of you have 19VLTP22's hanging around, you can just plug them right
into the Amplifone setup, or swap neck keys and put them into Wells
Gardners.

I want to see if the 19VJTP22 works any better, but I haven't gotten
around to trying that yet. My G07 has that tube, and I have an extra
one laying around .. so it would be neat to try.

Joel-
Received on Wed Oct 29 14:06:19 1997