I’m getting the fets from future electronics .
I’m using a Hakko FX-888D for the soldering
Iron
Never had an issue with parts from them before and never had an issue with an amp destroying so many parts .
Usually I just replace the defective parts make sure everything checks good and have no issues
I’m using a Hakko FX-888D for the soldering
Iron
Never had an issue with parts from them before and never had an issue with an amp destroying so many parts .
Usually I just replace the defective parts make sure everything checks good and have no issues
0.4 ohms on all of them .
The power supply fets are surviving this time around now it’s the outputs i’m having issues with .
I replaced all of the transistors on both driver boards with A1220/C2690 o also replaced the LM361 .
If the Tl072 is defective would that cause this issue ?
I unsolder the bridge between pins 13 and 14 before I powered the amp up and it stayed powered up for around 30 secs and played distorted audio then the outputs started blowing everything was clamped to the heatsink
The power supply fets are surviving this time around now it’s the outputs i’m having issues with .
I replaced all of the transistors on both driver boards with A1220/C2690 o also replaced the LM361 .
If the Tl072 is defective would that cause this issue ?
I unsolder the bridge between pins 13 and 14 before I powered the amp up and it stayed powered up for around 30 secs and played distorted audio then the outputs started blowing everything was clamped to the heatsink
I don't think a bad TL074 could cause this.
The transformer is likely causing the low readings.
Does it have a 3-prong plug?
Does your 12v power supply have a 3-prong plug?
The transformer is likely causing the low readings.
Does it have a 3-prong plug?
Does your 12v power supply have a 3-prong plug?
Maybe I misunderstood what you said .
You said what is the resistance from the mains power plug to the tip .
What do you mean by this ?
You said what is the resistance from the mains power plug to the tip .
What do you mean by this ?
To the tip of the soldering iron.
Does the soldering iron have a 3-prong plug?
Does your 12v power supply have a 3-prong plug?
Does the soldering iron have a 3-prong plug?
Does your 12v power supply have a 3-prong plug?
With the black probe on my 12 volt power supply ground and red probe on tip of soldering iron I get
15 volts of AC
0.07 volts of DC
15 volts of AC
0.07 volts of DC
15v AC with a meter may be over 20v and it could be damaging the FETs. Looking at it with your scope could be more conclusive.
With a scope I only get about a volt of AC voltage .
Do you have a pic of the audio driverboards to make sure I put the transistors back in the correct location ?
I noticed the outputs will blow after about 30 secs and the outputs will get very hot .
I will also check some other stuff in the general area to make sure everything checks ok .
Do you have a pic of the audio driverboards to make sure I put the transistors back in the correct location ?
I noticed the outputs will blow after about 30 secs and the outputs will get very hot .
I will also check some other stuff in the general area to make sure everything checks ok .
If you have rail-rail oscillation, the drivers are in the correct locations.
What are you using for N-channel FETs?
What are you using for N-channel FETs?
The amp had IRF640N’s in it when I got the amp in but the outputs were blown and someone tried to repair it before so I figured that’s what they were using IRF640N/9640’s in the amp .
But this is the 3rd set of outputs the amp has blown almost instantly
But this is the 3rd set of outputs the amp has blown almost instantly
You can't have rail-rail oscillation without the outputs.
These amps are marginal with any 640. The IRFB31N20Ds are much better.
Are the FETs failing because they're overheating because they're not clamped?
These amps are marginal with any 640. The IRFB31N20Ds are much better.
Are the FETs failing because they're overheating because they're not clamped?
I cut the bad outputs out of the amp .
With the remaining outputs still in the amp I have no rail to rail oscillation on any of the remaining outputs .
The fets were clamped to the sink when they originally started blowing.
With the remaining outputs still in the amp the amp powers up fine and idles perfectly
With the remaining outputs still in the amp I have no rail to rail oscillation on any of the remaining outputs .
The fets were clamped to the sink when they originally started blowing.
With the remaining outputs still in the amp the amp powers up fine and idles perfectly
It's not idling perfectly if there is no rail-rail oscillation.
Why did you remove the jumper from the TL074?
Why did you remove the jumper from the TL074?