Replaced the opamps and regulator .
The hum is still present but I noticed the voltage changes on the pins of U17 if I mess with the gain pot
The hum is still present but I noticed the voltage changes on the pins of U17 if I mess with the gain pot
You can't do anything until you get the proper supply voltage on U1-U3. All get power from the same supply. How can you have different voltage on their power supply pins? A burned trace seems like the most likely fault.
Here are the voltages I get on these
U9 A 2211
Pin 1:0.00
Pin 2:4.59
Pin 3:3.22
Pin 4:0.00
Pin 5:-10.23
Pin 6:0.08
Pin 7:6.19
Pin 8:9.17
U8 LM6171
Pin 1:0.00
Pin 2:-5.21
Pin 3:0.00
Pin 4:-9.77
Pin 5:0.09
Pin 6:7.84
Pin 7:9.73
Pin 8:0.01
U7 LM6171
Pin 1:0.04
Pin 2:0.02
Pin 3:0.01
Pin 4:-9.77
Pin 5:0.03
Pin 6:-5.62
Pin 7:9.72
Pin 8:0.10
Do these voltages appear to be correct or do I have a problem with one of them since I can’t find anything else defective
U9 A 2211
Pin 1:0.00
Pin 2:4.59
Pin 3:3.22
Pin 4:0.00
Pin 5:-10.23
Pin 6:0.08
Pin 7:6.19
Pin 8:9.17
U8 LM6171
Pin 1:0.00
Pin 2:-5.21
Pin 3:0.00
Pin 4:-9.77
Pin 5:0.09
Pin 6:7.84
Pin 7:9.73
Pin 8:0.01
U7 LM6171
Pin 1:0.04
Pin 2:0.02
Pin 3:0.01
Pin 4:-9.77
Pin 5:0.03
Pin 6:-5.62
Pin 7:9.72
Pin 8:0.10
Do these voltages appear to be correct or do I have a problem with one of them since I can’t find anything else defective
Back to this amp .
I have proper supply voltage on pins 4-8 of U1 thru U3 + - 13 volts
U4 I only have 9 volts on pins 4 and 8 is this correct or is something pulling the voltage down or I have a bad connection or part somewhere ?
I have proper supply voltage on pins 4-8 of U1 thru U3 + - 13 volts
U4 I only have 9 volts on pins 4 and 8 is this correct or is something pulling the voltage down or I have a bad connection or part somewhere ?
I replaced all of the Tl072’s in the preamp section .
Replaced the outputs checked all the resistors in the preamp section everything tests fine.
I get distorted audio still and the audio cuts in and out .
What am I missing here I’ve checked a lot of components and they all seem fine but the problem is still there
Anyone have any ideas ?
Replaced the outputs checked all the resistors in the preamp section everything tests fine.
I get distorted audio still and the audio cuts in and out .
What am I missing here I’ve checked a lot of components and they all seem fine but the problem is still there
Anyone have any ideas ?
Is this new? I thought that the amp only previously had a hum.
Post a photo of the distorted waveform.
Post a photo of the distorted waveform.
The hum went away .
Now the audio is distorted and the audio cuts in and out .
I will post a waveform when I get home .
Now the audio is distorted and the audio cuts in and out .
I will post a waveform when I get home .
Ok my scope won’t lock onto a waveform yet I think it’s time for a new scope .
I measured directly across the speaker terminals and I get 1 volt of DC and you can see it push out the test speaker also .
So my problem is that I have DC on the output
All of the outputs are brand new .
Any ideas where to check to see where the DC is coming from ?
I measured directly across the speaker terminals and I get 1 volt of DC and you can see it push out the test speaker also .
So my problem is that I have DC on the output
All of the outputs are brand new .
Any ideas where to check to see where the DC is coming from ?
Don’t know what happened but no I have full rail voltage across the output terminals but all outputs still test fine and amp is stuck in protection mode
It blew the outputs so I will replace them and go from there .
If I remember correctly pin 1 of U4 had like 9 volts on it .
Do either one of those U17 or U4 appear to be defective ?
Since I have to order outputs wondering if I should order anything else ?
If I remember correctly pin 1 of U4 had like 9 volts on it .
Do either one of those U17 or U4 appear to be defective ?
Since I have to order outputs wondering if I should order anything else ?
Discharge the rail caps and desolder the rectifier end of the red/black wires for both supplies and leave them disconnected. Solder a jumper across pins 2 and 6 of U17 and get a good drive signal at all FETs before you reinstall the outputs.
Ok both MIC4420’S are brand new .
I get good drive signals on half the outputs the other half of the outputs the drive signal is missing .
Any ideas on where to start checking ?
I get good drive signals on half the outputs the other half of the outputs the drive signal is missing .
Any ideas on where to start checking ?
I have drive signal back to the other half of the outputs had a broken solder connection .
But now the drive signal is very distorted so I will have to go they the circuit and see what’s causing the issue
But now the drive signal is very distorted so I will have to go they the circuit and see what’s causing the issue
Should I get identical drive signal on all of the outputs ?
I don’t get it half the outputs drive signal is fine the other half looks like it’s ringing
I don’t get it half the outputs drive signal is fine the other half looks like it’s ringing