If my experience is any indication, many of you have probably gotten an EVOD, ProTank or Viva BCC head that appears to have low resistance or a short. I've had a few EVOD and ProTank heads act this way, both right out of the box and after a few tank fills, so I thought I'd pass along a photo of a common problem with these heads that may save new users some aggravation.
The Problem
The issue is that the positive coil wire is making contact with the negative body of the base resulting in a short. In this case, the ZMAX detected the issue as resistance being too low. An initial test on a multimeter showed the correct 2.2ohm resistance and it wasn't until a little pressure was applied to the center post that the short happened. Removing the coil head from the base revealed the problem.
As you can see in the photo above, the cause of the short is that the positive wire from the coil is sticking out beyond the silicon gasket. It's easy to feel the protruding wire when turning the head between your fingers. When the coil assembly is screwed into the base, this wire may make contact with the outside of the tube, causing a short.
During the manufacturing process, the positive and negative coil leads are bent over the sides of the gasket and tube, respectively, to hold them in place when everything is assembled. They should then be trimmed and pressed in flush with the tube, but that obviously has not happened. Questionable quality control strikes again.
The Fix
Luckily, it's an easy fix. Simply inserting your thumbnail between the bottom post and the gasket and then turning the head in a counter-clockwise motion should be enough to push the wire back underneath the gasket. It may take a couple of tries because of the springiness in the wire. You should feel no wire protruding if you spin the head between your fingers now. You've just recovered a head that seemed defective!
The Problem
The issue is that the positive coil wire is making contact with the negative body of the base resulting in a short. In this case, the ZMAX detected the issue as resistance being too low. An initial test on a multimeter showed the correct 2.2ohm resistance and it wasn't until a little pressure was applied to the center post that the short happened. Removing the coil head from the base revealed the problem.
During the manufacturing process, the positive and negative coil leads are bent over the sides of the gasket and tube, respectively, to hold them in place when everything is assembled. They should then be trimmed and pressed in flush with the tube, but that obviously has not happened. Questionable quality control strikes again.
The Fix
Luckily, it's an easy fix. Simply inserting your thumbnail between the bottom post and the gasket and then turning the head in a counter-clockwise motion should be enough to push the wire back underneath the gasket. It may take a couple of tries because of the springiness in the wire. You should feel no wire protruding if you spin the head between your fingers now. You've just recovered a head that seemed defective!
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