I am upgrading a working Hitachi HMA-120 AV power amp and found a PCB area that looks overheated. It contains four 470 Ohm resistors and three zener diodes that are part of the power supply. Both resistors and zeners are soldered in such a way that they touch PCB which might cause overheating. I'd like to replace them; however, I don't know what to replace zeners with.
All three of them are of the HZ3C3 type and have min zener voltage 3.3 V and maximum 3.5V with 500 mW power dissipation. Should I replace them with three zeners of the same voltages but perhaps 1W dissipation or I can use one zener of 11.9V/2 W?
All three of them are of the HZ3C3 type and have min zener voltage 3.3 V and maximum 3.5V with 500 mW power dissipation. Should I replace them with three zeners of the same voltages but perhaps 1W dissipation or I can use one zener of 11.9V/2 W?
