BX765X (Algemeen)

door castafiore2010 , Winsum (Gn.), 04.03.2014, 14:43 (3920 dagen geleden) @ Pandu Rajan

Oh, there is a lot that you can check still. At first check how fresh the rectifier tube (AZ4 or AX50, I don't know which one is used) still is; when it has sunk under its capacity the sound becomes shallow. Then check the feed-back circuit around the output transformer. When you dispose of an audio signal generator and a dual beam oscilloscope, compare the sinus from the signal generator, connected to the input of the amplifier stage, to the sinus that comes from the loudspeaker connection. This gives you probably the best insight in what's wrong.

Then - how do the soldering points look on the output transformer? When they look very oxidated remove the old solder with an solder-sucker and solder the connections anew. It would not be the first time, when -through oxidation - these connections have become faulty & so on & so on.

Look carefully at the circuit diagram if every component is mounted and connected the way it should be connected according to the circuit diagram - also in the manufactory things went wrong from time to time. That is all I can say about it so far.

Good luck!