Amp cam in with blown outputs and the output filter inductor broken off the board .
Fixed the inductor and replaced all outputs with matching date codes .
Amp will power up and idle fine .
Problem is the amp has very distorted output .
Any ideas on where to start ?
Fixed the inductor and replaced all outputs with matching date codes .
Amp will power up and idle fine .
Problem is the amp has very distorted output .
Any ideas on where to start ?
I think my scope finally died it won’t lock onto anything
Anything else I can check to see if it’s causing the distorted outpu
I noticed I get half a volt of dc measured directly across the speaker terminals
Anything else I can check to see if it’s causing the distorted outpu
I noticed I get half a volt of dc measured directly across the speaker terminals
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For a sub amp, a sine wave between 50 and 100Hz is typically good.
Did you try viewing a PS waveform to see if the scope would work normally?
Did you try viewing a PS waveform to see if the scope would work normally?
Scope works when viewing the waveform of the power supply .
Just doesn’t work correctly when trying to view sine waves for some reason
Just doesn’t work correctly when trying to view sine waves for some reason
Remember to post the vertical amp and timebase when posting a scope image.
Can your scope lock onto the signal on the back of the RCA jacks?
What do you see on pin 7 of U303. Set scope to 5us and 2v/div.
Can your scope lock onto the signal on the back of the RCA jacks?
What do you see on pin 7 of U303. Set scope to 5us and 2v/div.
With that same scope setting, if you touch the probe to the 12v power supply positive, does the trace go off of the top of the display?
I just noticed something .
On Q427,428,411,412 I get no rail voltage on the outputs is this normal ?
On Q427,428,411,412 I get no rail voltage on the outputs is this normal ?
On u301 and 302, what's the DC voltage on pin 6 of each IC?
Do you have a triangle waveform on pin 5 of each of those ICs?
Do you have a square wave on pin 7 of U301?
Do you have a triangle waveform on pin 5 of each of those ICs?
Do you have a square wave on pin 7 of U301?
U301
Pin 6:-1.90
U302
Pin 6:1.90
I have triangle wave on pin 5 of both ic’s
I do not get a square wave on pin 7 of U301
Pin 6:-1.90
U302
Pin 6:1.90
I have triangle wave on pin 5 of both ic’s
I do not get a square wave on pin 7 of U301