Firstly thanks for your continued help.
So I’ve looked at the power in socket and it looks just like a socket. Couldn’t see anything that would suggest some form of electronic switching.
(Tried to provide a closer picture)
The resistance is 50 ohms created by the two 100ohm resisters in parallel. They are in series to the negative of the battery group and the pin that feeds the negative that would go to the Lynx.
I’ve also put my ohm meter from that pin to the negative part of the plug that would be inserted into the Lynx and that gives zero ohms.
My volt meter states that the batteries as a group are at 8.5v (I’m not sure what voltage they should be at all fully charged but as they are 1.2v, 24000mAh each I’m assuming that voltage is ok)
I just don’t know enough about electronics to know what’s going wrong.
I think I’m just going to give up on it.