Kingham solar panel not working

1. Can anybody point me in the right direction to check my solar panel not working at all , no it's not through lack of sun , though it should be , any ideas , before I start stripping things out looking for the obvious.Thank you Ron B
   

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Trace the wires coming through the roof into the solar controller, at the controller there'll be a solar input terminal. Disconnect just the +ve wire from that then measure between the +ve and the adjacent -ve. The voltage you could see will depend on the panel capacity, to give an idea, my 100W one is circa 22vdc. Need to be daylight though!

Thanks for that Ian , will get onto that asap , much obliged. Ron B