Hello, my English is not very good but I will try to explain myself.
I am repairing a sovereing Jaguar Xj4 and I have a problem with the radio.
After checking some cables and proceeding to connect with a 12v power supply. The radio tries to turn on but without power. This one doesn't turn on at all. I have tried several models and the same thing happens. The power supply is not capable of giving the full potential and I don't understand it since it is enough when I measure it with the multimeter. I don't know if there is any relay that cuts off the supply or what happens. All this without even connecting the speakers. I would appreciate help!