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If you look at the latest manual on Clark's site there is a different comment
AUX Power on/off (Only available when Main Gun Function Mode is set to Gun elevation servo Mode). If you scroll further down to where it deals with the connections you will see that auxiliary power uses pin 4 and 5 of CN9. It will turn on and off whatever you have connected as auxiliary power. Note that this only applies in relation to Heng Long tanks. http://www.clark-model.com/eng/prod_rx20/index.html
Richard
Tamiya Tiger 1, Taigen FlakPanzer IV,Torro M16 half-track, Tamiya Panther,WSN/Torro T34,Taigen M41 Bulldog,H/l/Taigen Sherman M4A3,H/L T90, Haya M3 Grant, Metal Origins 234/2 Puma, Nashorn by Alwyn. I was only going to have one tank - honest!