With no power applied. Measure the resistance from leg 1 of MOSFET 1 to leg 1 of MOSFETs 2, 3 and 4.
Do you get the same resistance for all 3?
What is the resistance?
Do you get the same resistance for all 3?
What is the resistance?
Ok Perry
this is the measurements
for leg 1 of MOSFET 1 to leg 1 of MOSFETs 2 : 20.1ohms
for leg 1 of MOSFET 1 to leg 1 of MOSFETs 3 : 20.3ohms
for leg 1 of MOSFET 1 to leg 1 of MOSFETs 4 : 20.1ohms
i Have just a little difference for mos 1 to mos 3
is it normal ?
thanks for your help 🙂
this is the measurements
for leg 1 of MOSFET 1 to leg 1 of MOSFETs 2 : 20.1ohms
for leg 1 of MOSFET 1 to leg 1 of MOSFETs 3 : 20.3ohms
for leg 1 of MOSFET 1 to leg 1 of MOSFETs 4 : 20.1ohms
i Have just a little difference for mos 1 to mos 3
is it normal ?
thanks for your help 🙂
I think there may be a problem with the measurements. If all of the gate resistors are intact and they are all driven from the same source, the readings should be identical. Unless you can determine why they're not identical, I don't think I can help.
0.2 ohms is insignificant. What IS significant is the difference in the readings he got when he measured the voltage from leg 1 to leg 3. It was too much of a difference (for me) to make any sense of the readings. They should have been identical.
reading legs of fets while amp runing is impossible to get and good reading, while they should be the same, they may as well be shown totaly diffrent, cheap multimeter just won't do at some point on
With no audio input, the voltage should be steady enough. Even if it's being driven to produce the rail-rail square wave on the outputs, the meter should give consistent readings. If he got consistent readings on one transistor (he stated that he re-check the readings), it should be the same on the parallel FETs.
I don't know why he needs to check this, if amp has DC voltage for rails, fets are working isn't this so... I don't know where he has problem now, I didn't read this thread a long time
He has DC on the outputs before the end of the mute delay. I want to determine why the DC is being driven to the speaker outputs. It could be that the outputs are being driven on, or it could be that they are leaking. If there is not enough voltage to drive them on, he likely has one that's leaky. If they are being driven on and that's causing the DC, then we'd need to follow the drive signal back to see if the problem is in the drivers, opto-couplers, the driver board or something feeding the driver board (unlikely since he had virtually no DC on the op-amp feeding the signal to the driver board and it's AC coupled to the driver board).
Honestly, I have never worked on one of these amps so I'm relying heavily on the information I'm getting from him. If you have more experience and can better guide him through the repair procedure feel free to do so.
Honestly, I have never worked on one of these amps so I'm relying heavily on the information I'm getting from him. If you have more experience and can better guide him through the repair procedure feel free to do so.
No no, you are doing fine, I can tell you what we do with this amp here when they go, they sure don't see the day of light 😀
I guess you are looking at amplifier, not the supply section
I guess you are looking at amplifier, not the supply section
He stated that the amp worked properly after the end of the mute delay so I don't suspect the supply. If you know of something in the supply that can cause this, let us know.
I had no broken SLA, the ones that were broken, whey had normal problems, like dead supply fets, amp fets, something like that... probably even something like DC on output, but to have that, duty cycle shouldn't be the same, that's why DC would be on output...dc on output even with load connected? is this what he is referring as "pop"?
It appeared that the amp produced ~2.5v on the speaker terminals when remote voltage was applied and precisely when the mute drive voltage transitioned from high to low, the voltage dropped to ~0.2v which I assume caused the pop he heard.
There are some things I don't know (and would have to try to determine from further troubleshooting) like does the amp oscillate before the end of the mute delay or does the oscillation begin when the mute drive voltage goes to ground.
There are some things I don't know (and would have to try to determine from further troubleshooting) like does the amp oscillate before the end of the mute delay or does the oscillation begin when the mute drive voltage goes to ground.
Hello
Thanks you for your help
so do you think i can try to replace 8 mos-fet in the amp ? what can i do
i don't want to use the amp before repair it because i think it can be destroy my subwoofer
Thanks you for your help
so do you think i can try to replace 8 mos-fet in the amp ? what can i do
i don't want to use the amp before repair it because i think it can be destroy my subwoofer
for the mos-fet it's IRF640N
and for the modu1 dou you know where can i find it please ? maybe it's that who is defective?
and for the modu1 dou you know where can i find it please ? maybe it's that who is defective?
Hello
No Perry i haven't do that, so have you got an idea to resove the problem please ? and do you think i can use the amp without risk to destroy my subwoofer ?
thanks for your help
No Perry i haven't do that, so have you got an idea to resove the problem please ? and do you think i can use the amp without risk to destroy my subwoofer ?
thanks for your help
2v DC for 2 seconds won't hurt any woofer that can take the full power from that amp.
I don't have any suggestions without more troubleshooting and it may not be able to be done without a scope.
I don't have any suggestions without more troubleshooting and it may not be able to be done without a scope.
So i think i'll buy a new amp because i haven't a scope....and maybe few years later i can repair it with your help
I thank you Perry for the help you brought me from the beginning 🙂
I thank you Perry for the help you brought me from the beginning 🙂
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