Hi B,

When you power up the 4YF you should see both the red and the green LED's on, if the red LED starts flashing, it means that the voltage has dropped to an unsafe level.

We hope to have the 4YF manual online soon so that it can be downloaded by our customers.

I hope you find this information helpful. You can also reach our Futaba support technical team at 217-398-8970, or via fax at 217-398-7721.

Sincerely,
Krysta
Lead Futaba Customer Service and Programming Technician
Also you may want to check our Website at (http://www.futaba-rc.com)