Smart Tech Dryer Internal Comm Loss Troubleshooting

Issue: Smart Tech dryer showing internal comm loss on the display and shuts down or continues to run.

Operation: Internal comm loss will be displayed when any one of the three boards in the dryer loses communication either due to a board failure or connectivity issue. The dryer may continue to run normally however the normal display showing operating conditions will not be displayed.

Troubleshooting Steps:

Ensure the serial communications cables are securely plugged into each of the boards in the dryer. The serial communications is a 3 wire plug with a black wire, red wire and a drain wire (black or clear shrink tube). In addition to ensuring the plugs are all fully seated onto the connector, ensure that the wires are properly crimped into the terminal by gently pulling on each wire as it goes into the connector.

On the display and sensor boards the communications plug is the J5 connector.

On the ATS Interface board the communications plug is the J6 connector.

If all the wiring connections are secure, observe the status display LED lights on the boards. The status display LED on the display board is the large LED in the upper right corner above the screen. On the sensor board the LED is on the right corner of the board next to the humidity sensor and on the ATS interface board it is located near the J6 serial communications connector.

The comm loss failure can originate from any of the boards and can be difficult to isolate which one is causing the issue without replacing a suspected board with one that is known to work. A visual inspection of each board may help identify the issue. If a board has gotten wet or has visible signs of corrosion this is usually the cause of the comm loss issue.

Another step to identify the issue is to observe the status LED on each board. Typically, two of the boards will display the same status and one of them will be different. For example, two boards may show blinking red and one board may not show any status or show solid red or green status. The board that is displaying a different status is normally the one causing the communications issue and should be tested first by replacing it with a different board to see if the issue persists.

Smart Tech Circuit Board Part Numbers

Display Board: 99045

Sensor Board: 100529

ATS Interface Board: 100530