I have two Buzzes.......One works well......the other not so good......

Looking for a remedy in fixing the 'sick' Buzz
Even when the Blue light comes on, my vapor is VERY weak. It is nothing compared to my newer Buzz. I have tried switching the attys between the two Buzzes and Buzz #1 always underperforms. Any suggestions would be appreciated.
SICK (older) Buzz #057
batteries charged ?? ( use a voltmeter if you have one , they should read 4.2 volts each ) YES
Take off the atty /carto first
Do you have a RED LED light ? YES
DO you have a Blue Led light when the button is pushed. SOMETIMES
DO you have a Blue led with the ATTY/CARTO ON the unit ? SOMETIMES
Do you have BOTH red and Blue led lights ? SOMETIMES
Do you get a blue led with the atty/carto ON but no vapor ? I GET VERY WEAK VAPOR, sometimes no vapor at all.
I am very happy with my newer Buzz and am considering ordering another Buzz, but I would like to fix Buzz #1 also.