Hyper st electric problem

Hi All, newby on this forum.
Talk slow and LOUD so i get it...........fnar fnar

I have listed the same question on the truggie thread as well. I'm not sure wether its a car or electric problem............Damn annoying though!!!!!

I have a new Hobao Hyper st rtr with a problem. i think its on the receiver battery side.
When we run it with standard (duracell AA bateries) it works for 30 mins. When i run it with the battery pack i was recomended it lasts for 20 minutes.
after these times the steering servo still works but the throttle doesnt. untill we switch trans and recev of and on again, then we get another 5 minutes till the same happens.
Apparently the servos are uprated, H-103 and H-102.
There is a fail safe fitted and the light works.

We have tried different hand unit, still does the same.

Are the batteries/batterypack (1400) not strong enough, or is something draining the batteries and the fail safe kicks in.

Or is it something tottaly different?

It was bought second hand from a local rc shop that they took as a trade in, but it had never been used. no spilt nitro stains, no scratches no dirt in those hard to reach places. I think it had been bought and put on a shelf.

Any ideas y'all out there in nitro land.


Cheers

Big Chris