ok, the short is gone but now I have no air flow.
I takes some experimentation to get it working. To me it sounds like the tubing is too long. Take a good look at the threaded part of the bottom of the A7. You should see two tiny holes, 180 degrees apart, right where the top of threads end. If those holes get covered by your tubing insert - no airflow.
What has worked for me, based on other's suggestions, is to snip off a ring from a carto condom no more than an 1/8" wide. Then cut thru the ring once. You should now have a strip that is 1/8" wide by about 1 1/4" long.
That 1 1/4" length will be way too long to fit into the gap between the center post and the thread post. Just trim it down gradually until it makes a near complete circle. I use a pair of really pointy tweezers or a dental pick to wedge the strip in, after backing out the center post as much as possible. Then I slowly screw the center post in until it is flush with the thread post. So you've now got basically, a bushing between the center and thread post.
Good thing is you only have to do this once. Its a shame they designed the A7 with a wobbly center post and no insulator between the center and thread post. I like them, but they made a mistake. I guess that's one of the reasons they cost less than $20... Good luck.
