i am working on an emphaser ea 15000 spl.all outputs on the left side are burned.
i removed them and also the audio driver board.
i power up the amp and the relais engage.power supply is working....
there are two 7812 regulators (photo) in parallel mode.the input voltage is the same as the output voltage 14,8v
black probe center leg,red probe on pin 1 and 3.so pin 1 and pin 3 read the same value.
are they defective?
i removed them and also the audio driver board.
i power up the amp and the relais engage.power supply is working....
there are two 7812 regulators (photo) in parallel mode.the input voltage is the same as the output voltage 14,8v
black probe center leg,red probe on pin 1 and 3.so pin 1 and pin 3 read the same value.
are they defective?
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It's supposed to be over-voltage protection but on some boards, it's not connected to anything. I've also seen it connected as low voltage protection but I think that was on boards with two comparators on the power supply board.
i removed the rectifiers to troubleshoot the audio driver board.the square waves are present as they should be.on pin 1 of the 21844 i can also see the square wave.
the outputs are still in circuit.
is the 21844 able to produce output without the rectifiers?
the outputs are still in circuit.
is the 21844 able to produce output without the rectifiers?
If the IC has 12v feeding it, you will have low-side pulses. To get high-side, you'll likely have to provide high-side voltage. A 9v battery works.
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