Hi Kevin and Six shooter, Sorry that I get back to you late reply. I have been busy test fly both of my airplanes for the last few days at our local jet meets. What happens was my new Hotspots air brakes servo stalled in close position. Thanks to Bob Wilcox (JetCat USA) and Tony Frackowiak found out the problem. What gave indication was everytime we close the airbrake and ready for taxi for takeoff, the P120 keep shut down and indicate power failure on the GSU. Both of my Hotspot and Yellow F4/Ram500 flies very nicely. The voltage regulator I use is from Cermark.
Thanks everyone for your help.
Daniel