hello everyone!
found a pair of pc speakers in recycling room( wrong place to discard electronics...) and hoped that wont work so I can learn more about electronics and my wish came true:))) but now I cant figure out what the problem is...
-symptoms:
sounds OK up to about 10% of the volume, anything after that sounds distorted.
-what I have checked so far:
1)looked for shorted wires, but doesn't sound like shorted wires because it sounds clear up to 10% of its volume
2) found a leaky capacitor, checked it with ESR meter, much higher resistance than what it should be... replaced bad capacitor and same symptoms...
Brain of this little amp is a TEA2025B chip... everything else on the board is only caps, 1 pot for the volume(also is for on or of )and 1 transistor which i pulled it out of the board and it checked good.
Any guidance would be much appreciated and thanks in advance!!!
1st rule of electronics repair: measure voltages!
1st rule of electronics repair: measure voltages!
Any wake up call its more than welcome, but guidance would more appreciated...
Well, have you actually measured voltages? If you did you didn't mention it, just testing caps and a transistor, something beginners will often do while forgetting about voltages.
a) As everyone's mentioned, measure voltages. Without that basic level of troubleshooting you're not fault-finding, your guessing.
b) Dunno about that chip particularly but most similar ones of that time & ilk are notorious for either being really prone to supersonic oscillation unless the layout and surrounding circuitry is spot-on, or half-dying and distorting at higher volumes.
Voltages. Datasheet. Compare...