What is the best course of action when everything seems fine but there is no audio output?
All drive signals on the outputs look good.
All power supplies are there.
Relay kicks on and amplifier shows a green light.
The only real strange thing I see is there is "ringing" on the signal at the top of R33 on the output card.
All drive signals on the outputs look good.
All power supplies are there.
Relay kicks on and amplifier shows a green light.
The only real strange thing I see is there is "ringing" on the signal at the top of R33 on the output card.
If you ground your scope to the negative speaker terminal, does that give a cleaner signal?
Do you have audio on C120? You can touch the top of the cap to check for signal.
Do you have audio on C120? You can touch the top of the cap to check for signal.
Are you referring to the RCA shield as the audio ground?
DCV on pin 11 of the driver board?
This is type 7 in the tutorial if you haven't found it.
DCV on pin 11 of the driver board?
This is type 7 in the tutorial if you haven't found it.
I am using the negative speaker output terminal.
Voltage on pin 11 seems negligible. (.1701)
I have been re-reading the type 7 section.
Voltage on pin 11 seems negligible. (.1701)
I have been re-reading the type 7 section.
Do you have any modulation of the drive signal when you see audio on C120?
Near 0v is good on pin 11. In the future, please use a leading zero to the left of the decimal.
Near 0v is good on pin 11. In the future, please use a leading zero to the left of the decimal.
Anywhere that you have the 60K square wave, from the output of the driver board to the output FETs.
The compression software lacks something to be desired, but you can see the drive signal.
It looks like it is modulating. I am inputting a 50Hz sine wave.
Notice what happens when the relay clicks in.
It looks like it is modulating. I am inputting a 50Hz sine wave.
Notice what happens when the relay clicks in.
If you have modulation, you should have audio at the output.
Check for audio on the output filter inductor. Do you see audio there?
Is the relay closing?
Check for audio on the output filter inductor. Do you see audio there?
Is the relay closing?
The relay is closing.
I have signal @ L203, but not at L205.
I may have a bad solder joint.
I haven't taken the amp out of the heatsink,
I have signal @ L203, but not at L205.
I may have a bad solder joint.
I haven't taken the amp out of the heatsink,
Moving the inductors should show a bad solder connection. Possibly a burned/corroded trace?
Either way, you're right. a bad connection.
Either way, you're right. a bad connection.
I tried twisting them, but it didn't change anything. I'll take it out and let you know what I find.
There won't be much high-frequency signal beyond L203.
If driving a signal into the amp producing significant modulation, you will see a rail-rail square wave on the FET side of L203 and audio (with a tiny residual high frequency noise) on the other terminal of L203.
If driving a signal into the amp producing significant modulation, you will see a rail-rail square wave on the FET side of L203 and audio (with a tiny residual high frequency noise) on the other terminal of L203.
Perry, I want to thank you for your patience.
I believe that I have got this amp working. I am putting it back into the heat sink for more testing.
I do think that there was a bad solder joint, but it kept acting "flaky".
I started moving the gain pot ( I had it set to the center while I was checking) and low and behold, I have a good signal all the way through.
I believe that I have got this amp working. I am putting it back into the heat sink for more testing.
I do think that there was a bad solder joint, but it kept acting "flaky".
I started moving the gain pot ( I had it set to the center while I was checking) and low and behold, I have a good signal all the way through.
