Amp produces clean audio for a moment, or if turn up the volume produces only noise like a fault on the ps and the orange light turns on. I suspect for low voltage at rail (only positive rail for this amp), it only has 53 volts, and the caps are 100v rated.
JL amps are very sensitive to dips in voltage at the 12v supply input.
What's the amplitude (on the scope) of the square wave on the secondary side of the transformer?
What's the 12v input voltage at idle?
What's the amplitude (on the scope) of the square wave on the secondary side of the transformer?
What's the 12v input voltage at idle?
Constant 12v switching ps. No scope for the moment, only a graphic multimeter thats shows 30khz but cant see the waveform.
4.4 volts on all ps gates. The swithing transistors also replaced with 1gm and 2gm instead of za and zc. I use these transistor all time but not sure if its a problem on this amp.
4.4 volts on all ps gates. The swithing transistors also replaced with 1gm and 2gm instead of za and zc. I use these transistor all time but not sure if its a problem on this amp.
I test with only left half bridge and works ok. So the problem is in right half bridge, diode d15. I try with some diodes, no luck. I really need the exact part number. I will relocate the diode from left to right to test the other bridge.
The diodes in series with the gate resistors for the output FETs are 1N4148 types. I'd expect these to be the same.
Did the new diode fail?
If you power down and leave it off for a while, does it again work without noise?
If you power down and leave it off for a while, does it again work without noise?
The diode is ok. Sounds good some seconds then stills sound but with a high pitch noise in the back. The amp nows dont stop and dont protects. When i turn off with the remote wire the noise stills sound like a cap discharging.
I need to rest the amp a lot of time then turn on again sounds ok some seconds and the noise come back.
I need to rest the amp a lot of time then turn on again sounds ok some seconds and the noise come back.
Looking at the output terminals, does the noise exist on both positive and negative speaker terminals?
Do you have any component chiller spray or 'canned' air?
Do you have any component chiller spray or 'canned' air?
Both sides. More noise at the output with the original diode.
I notice noise from ps rail caps when i turn on without speaker.
I notice noise from ps rail caps when i turn on without speaker.
Canned air is a refrigerant. If you invert the can, it will dispense liquid. The liquid will freeze anything it contacts. Try cooling various areas/components to see if the problem is eliminated when the components are cold.
Updated
I try to repair again today. Ir2101 both replaced, missed diode replaced with 1n4148, both 10 ohm resistors, 1/2 rail voltage on both outputs. Plays fine no heating not strange sounds only humming sound all time but it stops when i jumps the rca shield to amp ground. I have 100kohm betwen ground and shield. Any ideas what is the problem here??
Thankss
I try to repair again today. Ir2101 both replaced, missed diode replaced with 1n4148, both 10 ohm resistors, 1/2 rail voltage on both outputs. Plays fine no heating not strange sounds only humming sound all time but it stops when i jumps the rca shield to amp ground. I have 100kohm betwen ground and shield. Any ideas what is the problem here??
Thankss
I dont know. I test with a Chromebook, i dont have this problem on another amps. I will test in my car tomorrow.