ce amplifier

Looking for answers, I have a Sony Shake 6D Hifi system and has E03 power supply tag error. However for some time. Unit is working like a couple of hours but after minutes sometimes E03 triggers. I did check the voltage. And they were nominal as indicated by the service manual. I have seen...

Hi. The schematic of amplifier using BJT and the result is attached. What I learned is that the beta, ratio of Ic/Ib, would be constant. However, the ratio of Ic/Ib varies by the time. I googled for this and found out that the beta varies with temperature and Ic but does it vary that much...