| Electronics > Repair |
| Class D Subwoofer Amplifier Repair |
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| geoffagain:
Ok so Zener in circuit ZD201 is 1N4744 15v The one I pulled from donor is also marked IN4744. So seems for whatever they're using 15V rather than 16V on this one. Tested ZD201 out of circuit with my bench supply and a 1k resistor - Seems ok, holds 15v upto the 20v I can supply. Not sure on leakage current. I'm not measuring any current or at least very minimal under 15V with a 1k resistor in series. Approx > 0.5mA at 15V 1mA at 16V 2mA at 17V 3mA at 18V |
| Harry_22:
Measure the resistance between D210 anode and pin 4 of IC201. There are also C209 capacitor in parallel with the zener. |
| geoffagain:
Cheers for your continued patience. Resistance between D210 anode and pin 4 of IC201 - same behaviour as before with D210 cathode and pin 4 of IC201 - rises quickly to OL then drops low then rises and settles at 9.6Kohm - perhaps still rising very slightly over time. I'll pull c209 and see what my ESR says. |
| Harry_22:
But with Zener you had 0 Ohm. Am I right? |
| geoffagain:
Sure ZD201 anode to pin 4 is 0hm |
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