1. Is the sucker fried?
Maybe.

2. What should you do:
Per Tamiya USA: If a product has a damaged or defective part, please contact Tamiya America's Customer Service Department at 1-800-TAMIYA-A.

Tamiya America, Inc.
36 Discovery #200, Irvine, CA 92618
Phone: (800) TAMIYA-A or (800) 826-4922 · Fax: (949) 362-2250

3. Long shot: Do you have WIFI?
If so, had a similar problem with an older (decade) Tiger IE DMD T-03, MF-01 controller set and putting a "rubber mat" to insulate, between the metal hull and the MF Unit and the DMD Unit sitting atop the MF Unit fixed the weird issue and restored operation to the controller set. The WIFI plus an older DMD Unit, MF Unit was the problem. The WIFI did not effect any of my other, newer, Tamiya DMD-MF controllers. The Tamiya USA Tech discovered the issue.