my amp is power up, i'm getting harmonic sound, when i put an input jack in and a bad humming out the output. need your help please. thanks i try to up load schematic.
sorry for getting back so late. i try at first with my my Leader audio generator and just to be sure i connected a kenwood cd player to it, and the humming noise won't stop, i dont do repair on a daily schedule it a when i get around thing for me. my power supplys are amrel pps 1326 adjustable 13v 0-5 amp and astron 12v-20a i use on my work bench. here is what i don't understand why i'm getting 80volts on Q7 Q8 Q7A Q4 Q6 Q2A and other 6 output i'm only 36.05 volt from gate voltage,
What's the resistance between the RCA shields of the signal sources and the ground of the 12v power supply?
What's the DC voltage on each of the speaker terminals? Black probe on the primary ground.
What's the DC voltage on each of the speaker terminals? Black probe on the primary ground.
hi, Perry just got in, on the positive speaker terminal voltage is 40.02 volt and on the neg it is 39.84 volt. Resistance between RCA shields is 111.6k ohm
The head unit needs to be grounded to the same ground as the amp's main/primary ground terminal.
If that's what you have, you have an open shield ground on the head unit.
If that's what you have, you have an open shield ground on the head unit.
No i dont think it is the head unit, even when i install it in the customer car with new RCA new head unit it hums, i remove the RCA socket from the board to check if one of the pin was broken everything was find there, could you tell me what the resistance i'm looking for with respect to power ground, and i measure the signal across the shield it,s around 60.05Hz, resistance across the RCA drop a little once i move the rca socket and resoldered it back.
You stated that it hummed in the car. Did you have anything in the car connected to the 120/240v mains supply?
No this started from when i got it in for repair, and to the car issue No.' what the resistance i'm looking for with respect to power ground from RCA shield
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I'm having trouble understanding your answers.
Try this again:
What's the resistance between the RCA shields of the signal sources and the ground of the 12v power supply?
Are you now saying that there was no hum in the vehicle?
Try this again:
What's the resistance between the RCA shields of the signal sources and the ground of the 12v power supply?
Are you now saying that there was no hum in the vehicle?
. Resistance between RCA shields and power ground is 111.6k ohm, sense spoken with you last, i try the amplifier out again and it didn't make the hummed sound anymore, thanks for the help well appreciate, but now it appeared like the amp is clipping when i turn the volume dial up, would it be fair to say base on the schematic i uploaded that IC1 NJM3403ad is not functioning,
What are you powering the head unit from?
Why aren't you using the same power supply as you're using for the amp?
Why aren't you using the same power supply as you're using for the amp?
Sorry for the confusion all i was trying to say at one point i had try the amplifier in my car and it gave me a humming sound too. but now i'm at my work bench and this is what happening now, Resistance between RCA shields and power ground is 111.6k ohm, sense spoken with you last, i try the amplifier out again and it didn't make the hummed sound anymore, thanks for the help well appreciate, but now it appeared like the amp is clipping when i turn the volume dial up, would it be fair to say base on the schematic i uploaded that IC1 NJM3403ad is not functioning, Test unit i am using now is a Astron 12Volt 0-20 amp power supply Leader signal audio generator, fluke 83 multimeter and HP 100mhz ocilloscope.
Are you using the same 12v power supply for both the amp and the head unit?
If so, you should read 0 ohms between the shields and the 12v power supply ground.
If so, you should read 0 ohms between the shields and the 12v power supply ground.