Hi
This HiFi amplifier uses two PA3002 power ICs for its L & R output and both have blown. This part is totally obselete. On checking on the net, as a replacement UPC1188H they say,can be used as a substitute. I replace both sides with this part. Now the problem I face is, when I turn on the amp, there is a loud hum but no audio and then if I turn the volume or bass up, the sound comes on but goes off, then comes on again and fades off. This keeps repeating and if I touch the chassis, the hums fades but comes on again. Is this a problem with the replacement IC or a power supply problem. The voltages to pin 3(+vcc) is +21V and pin10(-vcc) is -21V which is correct.
Thanks
This HiFi amplifier uses two PA3002 power ICs for its L & R output and both have blown. This part is totally obselete. On checking on the net, as a replacement UPC1188H they say,can be used as a substitute. I replace both sides with this part. Now the problem I face is, when I turn on the amp, there is a loud hum but no audio and then if I turn the volume or bass up, the sound comes on but goes off, then comes on again and fades off. This keeps repeating and if I touch the chassis, the hums fades but comes on again. Is this a problem with the replacement IC or a power supply problem. The voltages to pin 3(+vcc) is +21V and pin10(-vcc) is -21V which is correct.
Thanks
Hello. I have the same problem, I think the mute terminal works differently on the UPC, I tried connecting it directly to the VCC and those strange behaviors stopped. I have to keep trying, if someone else in the forum had this problem, could you please share their experience. Thank you so much.