roper dryer not drying in 'automatic'

[rancherman]

My electric Roper dryer in 'automatic' advances the dial to 'done' with about half the moisture removed.
I went through the whole machine and de-linted it. It wasn't too bad, as about a year ago, I had a foreign object in the blower, so when i got that out, I cleaned the machine at that time.

Dryer works great in the manual 30 minute HIGH HEAT mode. I can see through the peek a boo hole the elements glowing. But not when in automatic. I realize in this test, there were no damp clothes in it to signal the sensor to make it heat.

I thought when sensors failed, or had high residue build up on the sensor, they just ran and ran, either with or without heat.. this one advances the dial fairly quickly.. Usually less than half hour. Seeing that the heater is functional, blower is clear, and manual mode works good, is it safe to assume it's the moisture sensor?

 

[rancherman]

Better add some more info;

RED4400VQ1 model.

DOESN'T HAVE MOISTURE SENSOR in the drum. The 'cutout notch' is there for one. This is a cheaper model, and it isn't equipped with it.

So, 'cycling thermostat' the next suspect?

 

[DADoES]

 
Bad cycling thermostat could be the problem.  Thermostatic auto-dry has the timer not advancing while the heating element is on, does advance during the periods when the target air temperature is reached and the element cycles off.

However, the timer is advancing to Off on auto-dry.  You don't mention that the machine is running too hot (as if the cycling thermostat is sticking).

You say that you've "de-linted" the machine interior, cleaned the blower housing ... but have you checked the exhaust ducting for obstructed airflow?