ok it still measures good . Not sure what is causing the issue now . I checked all resistors around U1000/1001 all test fine . The voltage between pins4-8 for U3 29.85
pin 4: -4.86
Pin 8:29.85 volts .
the transformer is whining
not sure why it changed
pin 4: -4.86
Pin 8:29.85 volts .
the transformer is whining
not sure why it changed
You should be able to measure the pins 4 and 8 individually but there is a problem preventing it.
The reading of about 30v 4-8 shows the regulators are working.
Where are you placing the black probe when measuring the voltage?
What make/model meter are you using?
The reading of about 30v 4-8 shows the regulators are working.
Where are you placing the black probe when measuring the voltage?
What make/model meter are you using?
Black probe on main ground terminal when measuring the voltage on pins 4 and 8 .
The meter I have is a Klein tools
model MM600
The meter I have is a Klein tools
model MM600
If you take a 1k ohm resistor and connect it to a 12v source and measure the DC voltage on the terminal of the 12v supply and then on the loose end of the 1k resistor, what voltage do you read on both?
There is a large SMD resistor R1030 near U1000. What's the DC voltage measured directly across that resistor?
There is a similar resistor near U1001. Measure that voltage as well.
There is a similar resistor near U1001. Measure that voltage as well.
R1030:0.27
R1029:0.67
the amp works and plays clean audio but I still get the hissing whining from the transformer
R1029:0.67
the amp works and plays clean audio but I still get the hissing whining from the transformer
Most of this has been to try to find why the amp was whining so loudly but we got stuck on the regulator doing strange things. Will the owner be happy if the whining remains?
I think I figured out the issue with the whining .
There are a lot of cold solder joints on the board I touched a few of them up and it reduced the noise I will go over all of them and post back with the results
There are a lot of cold solder joints on the board I touched a few of them up and it reduced the noise I will go over all of them and post back with the results
Back to this amp .
not sure what changed but amp powers up and idles fine but even with no rcas plugged in I get a loud hum/popping through the test sub .
the transformer is hissing and I can hear it through the test sub and amp has no output
not sure what changed but amp powers up and idles fine but even with no rcas plugged in I get a loud hum/popping through the test sub .
the transformer is hissing and I can hear it through the test sub and amp has no output
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Does the PS intermittently stop oscillating when popping?
Do you ever see rail-rail oscillation on the output transistors?
Do you ever see rail-rail oscillation on the output transistors?
Are you 100% sure that the whining is coming from the speaker?
Do you read any voltage between the negative speaker terminal and the main ground terminal when there is no audio?
Do you read any voltage between the negative speaker terminal and the main ground terminal when there is no audio?
The transformer is whining hissing and through the speaker terminals it sounds like someone is farting through the test sub constantly
Something isn’t right in this amp .
i noticed I do not have the correct voltages on Q2010,2012,2001,2000
i noticed I do not have the correct voltages on Q2010,2012,2001,2000