Got this amp in and noticed 1 of the rail caps vented .
I replaced the rail caps and went to power the amp up and another cap that connects to the negative regulator vented .
Also noticed there is a burnt trace on the bottom of the board .
Any ideas what might cause this ?
I replaced the rail caps and went to power the amp up and another cap that connects to the negative regulator vented .
Also noticed there is a burnt trace on the bottom of the board .
Any ideas what might cause this ?
Attachments
Is the regulator producing too much output voltage?
Does one end of that burned trace go to any of the RCA shields?
Does one end of that burned trace go to any of the RCA shields?
Can I remove the cap and test the output voltage of the regulator ? And yes 1 end goes to to the rca shield ground
12v may have touched the RCA shields.
Did you repair the trace before powering the amp up when the cap vented?
Did you repair the trace before powering the amp up when the cap vented?
It also could have been a speaker output shorting to ground to burn that trace.
I'd repair the trace and check the voltage across the vented cap to see if the voltage is too high. Place the probes on the cap, power up only long enough to read the meter then power down.
I'd repair the trace and check the voltage across the vented cap to see if the voltage is too high. Place the probes on the cap, power up only long enough to read the meter then power down.
There is to much voltage across the cap . cap is rated at 16 volts and I get -17.88 volts measured directly across it
I don't think 2v would make a cap vent but I could be wrong.
Did you repair the trace?
What's the part number on the regulator?
Did you repair the trace?
What's the part number on the regulator?
I replaced both caps repaired the trace .
The 7912 regulator was defective I lifted the output leg and it was putting out 21 volts .
after replacing the negative regulator I noticed positive regulator os only putting out 2 volts .
so I have to replace the positive regulator and also another cap that’s on the input side since it exploded on power up
The 7912 regulator was defective I lifted the output leg and it was putting out 21 volts .
after replacing the negative regulator I noticed positive regulator os only putting out 2 volts .
so I have to replace the positive regulator and also another cap that’s on the input side since it exploded on power up
No it’s not working . I have to go down to the electronics store and get a 100uf 50 volt cap to replace the one that exploded .
Replaced the cap and the negative regulator is working I get -12.95 volts .
The positive regulator is not working with black probe on middle leg and red probe on output leg I get -0.75 volts
The positive regulator is not working with black probe on middle leg and red probe on output leg I get -0.75 volts
Ok I noticed there is a diode that is shorted also . It’s marked U1D.
Wondering can I use a ES2D diode in it for testing ?
Wondering can I use a ES2D diode in it for testing ?
Replaced the diode and amp is powered up and producing the correct regulated voltages . I’m going to put it back in the heatsink and test for audio