Why does my Spectrum RX need a cap?? SR3000

Hi there. Ive swapped out my Futaba 3003 with a GWS servo.
It seems some servos cause the rx to cut out (both GWS & Bluebird)
Plenty of power in the LRP esc's bec, its rated at 3A.
Ive added the cap to the RX to fix the problem, made one up.
http://www.spektrumrc.com/Products/D...ProdID=SPM1600

Is this a design issue of the RX, or is the LRP's 3A bec circuit just not up to the
job??
Or perhaps the servo causing interfernce on the 6v line, then cap then smoothing out any interference/hash, which is all a small cap is good for...

Any ideas??