Strong SRT 4400. whats wrong?????

Zebo

Hello guys. Ive got here a Strong SRT 4400, at first when I put it on to c whats wrong with it on the front display there was a message(booting startup)and tv screen (with no picture on) flickering. Also there was a constant ‘buzz’ coming from the transformer on the power supply. I thought I should first try to reprogram it, so downloaded the latest firmware from the official site together with its loader. At first the procedure failed but I tried again and it worked. But to my disappointment when I turned it on there was the same problem again, booting startup and then tv screen flickering again. I disconnect the power supply and the noise from the transformer stops. I checked the diods and stuff and the power supply and it seems to b fine but im not sure, but I think theres sumthing wrong on the motherboard. Could anyone give an advice? Thanx in advance