Welcome to the forum njb!
By "internal" I assume you mean inside your smoker. Most folks use the term "internal" for whatever it is they are cooking.
If you are getting satisfactory results with your smokes the first thing I would check is your your probe. Is it accurate - 32* in ice and 212* in boiling water.
Are you using an extension cord? Extension cords of a low gauge can reek havoc on the temps. You will never peak the smoker's tamp capability.
If both of these suggestions don't fit, call Cookshack. Their Customer Service is superb. They will make it right.
Good luck!