T-jet Armature Resistence Test

Here I will show you some simple steps to test your t-jet
Armatures. This is an resistence test to see if you have a bad Armature.
You will need a digital or analog Ohm meter.

Click on the image to make it bigger
arm01 arm02
First I get out my Ohm meter.
I use a fluke ohm meter because they are reliable and
in most cases affordable and cheap. ( depending on what
model you get). Start by setting your meter to "OHMS".
There are 3 solder contacts on a T-jet arm. You want to use
these contacts to make your measurements.
In order to be successful, you have to keep track
of which contacts you have measured. Start by putting
one contact away from you and mark it mentally as
point #1. Place one of your ohm meter probes on it.
Mentally mark point #2 to the left of #1 and place
your second probe on it.
arm03 arm04
Look on your ohm meter for the reading. On most older
armatures it should be around 18 ohms. The better RED
sided armatures are usually around 8 ohms. Mean greens
are usually around 6 ohms and quadralams ar usually 4.5
ohms. Some AF/X red sided arms are about 15 ohms.
Next, carefully rotate your armature 33 degrees to
the right, keeping track of the 2 contacts you
you have already measured.
arm02 arm03
Now place one lead of your ohm meter onto contact #2 and
the other lead onto contact #3.
Again, look at your ohm meter. The reading should be just
about the same as the first reading.
arm04 arm02
Now rotate your armature one more time 33 degrees
to the right. Keep track of which contacts you have
Next, measure contacts #3 and contacts #1 with your
ohm meter in the same way you measured the 1st two

Photo Copyrights by V.M. Churchill, 1998, All Rights reserved, No Unautherized Reproduction.