Hi everyone,
I am new to this forum as like as to Class D. But anyway, need some help.
Several months ago got blown Hifonics bxi1600d for reasonable price and just some weeks ago started to find the problem.
Firstly, after opening it, I found power supply's MOSFETs blown (many of them were just broken in halves, many had blown legs). Of course, there was just continuous current drain through the amp and nothing else. Fuses were good.
Replaced all 12 of mosfets with irf1404 and tried to check it. Nothing happened, but this time the TL494 was just trying to start as soon as the supply voltage was just over 8V. Seemed like there was a short somewhere in the amplifying section.
Got all 12 IRF3710's off the pcb, and found 2 of them shorted: one from Drain to Source and another one from Gate to Source. Replaced them. The amp was still in protection mode (red led). Tried to change the HIP4080AIPZ with new one and nothing happened.
What I have now:
1. Power supply is absolutely Ok. Mosfets are cold at 2Amps without any heatsink.
2. When all the IRF3710s and the HIP are out of the board, the green led is shining just like the AMP is ready. The voltage on big caps never exceeds +/-79.5V, current drain is about 1.7A at 14V and voltage between HIP's 4 and 15-16 pins is slightly over 13V.
3. When all mosfets are at their places, and the HIP is out of the board, the green led shines again.
4. When I put the HIP into the socket, the AMP goes to protection mode. The current is 1.8 to 1.9Amps and almost nothing is hot. The supply voltage of the HIP is again about 13V. The 1st pin have about 12.8V, the 10th has almost 80V - is this normal? At 3th pin there is also about 13V, looks like the AMP disables the HIP all the time.
5. When I put 3th leg of HIP out of the socket, the green LED starts shining, but there is no sound at the output.
What should I inspect else to get closer to solving this problem?
Know here is enough of them who has the experience in this kind of amps, especially based on HIP4080. So very hope on your help.
P.S. And sorry for my English, it's a little hard to describe all the situation just like it is.
I am new to this forum as like as to Class D. But anyway, need some help.
Several months ago got blown Hifonics bxi1600d for reasonable price and just some weeks ago started to find the problem.
Firstly, after opening it, I found power supply's MOSFETs blown (many of them were just broken in halves, many had blown legs). Of course, there was just continuous current drain through the amp and nothing else. Fuses were good.
Replaced all 12 of mosfets with irf1404 and tried to check it. Nothing happened, but this time the TL494 was just trying to start as soon as the supply voltage was just over 8V. Seemed like there was a short somewhere in the amplifying section.
Got all 12 IRF3710's off the pcb, and found 2 of them shorted: one from Drain to Source and another one from Gate to Source. Replaced them. The amp was still in protection mode (red led). Tried to change the HIP4080AIPZ with new one and nothing happened.
What I have now:
1. Power supply is absolutely Ok. Mosfets are cold at 2Amps without any heatsink.
2. When all the IRF3710s and the HIP are out of the board, the green led is shining just like the AMP is ready. The voltage on big caps never exceeds +/-79.5V, current drain is about 1.7A at 14V and voltage between HIP's 4 and 15-16 pins is slightly over 13V.
3. When all mosfets are at their places, and the HIP is out of the board, the green led shines again.
4. When I put the HIP into the socket, the AMP goes to protection mode. The current is 1.8 to 1.9Amps and almost nothing is hot. The supply voltage of the HIP is again about 13V. The 1st pin have about 12.8V, the 10th has almost 80V - is this normal? At 3th pin there is also about 13V, looks like the AMP disables the HIP all the time.
5. When I put 3th leg of HIP out of the socket, the green LED starts shining, but there is no sound at the output.
What should I inspect else to get closer to solving this problem?
Know here is enough of them who has the experience in this kind of amps, especially based on HIP4080. So very hope on your help.
P.S. And sorry for my English, it's a little hard to describe all the situation just like it is.
Can anybody help with my amp? There are almost all main components seem to be good right now, but the protection mode is still shining.. What to try?
Disconnect the power amp section. just leave the smps part without anything tied to the output.
it seems that the class d amp is fried also
it seems that the class d amp is fried also
The smps is working without any problem. Probably yes, there is a problem in amplifying section, but how can I find it out? Again, the HIP4080 is new from intersil and should not be fake (I hope).
Any more suggestions?🙁
Just checked mosfets and dual diodes at supply again, all are OK. The supply voltage is stable, no heat dissipation from output mosfets at all. Still unsure about the HIP - how can I check its working condition?
if you have an oscilloscope, try to see the signal that goes from the IC to the gates of the power mosfets.
also check the comparator that feeds the HIP with signal.
sorry for the late replies but i am at work
also check the comparator that feeds the HIP with signal.
sorry for the late replies but i am at work
There is 0V going to all 4 by 3 mosfets. They are closed. Thats what I see between 6 and 4 pins of HIP (on 1st pic), or about 50-55kHz signal with amplitude of about 8V. Took a photo of some ICs near the HIP. Dont you mean to check the LM393? There are 3 pics of them, how can I check them? Or it is better to change all 3 of them and check the amp? The supply is stable at 13.2V.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Have you checked if any of the MOSFETs in the amplifier output switching stage have got a short-circuit between the gate and either the source or drain?
Also check the same MOSFETs between source and drain. There should be a normal diode drop (0.6 to 0.7V) on N-ch MOSFETs if the source is more +ve than the drain. Easy to check if your multimeter has a 'diode check' function as an option on its resistance ranges.
Also check the same MOSFETs between source and drain. There should be a normal diode drop (0.6 to 0.7V) on N-ch MOSFETs if the source is more +ve than the drain. Easy to check if your multimeter has a 'diode check' function as an option on its resistance ranges.
Yes, I have already checked all 12 mosfets at amp stage (as it was described in my first post), there were 2 bad of them and yes there were both G-S and D-S short circuits, but now they are all OK (replaced).
Diode test was also OK. It seems like the HIP is in "mute" mode, as there is a high level at pin 3.
We know that the replaced FETs are ok, but what about their gate drive? Sometimes a resistor gets open or a diode or transistor shorted when a FET fails.
But by the sound of point 5 in post #1 it seems that the amplifier shuts down as soon as it starts to switch, this suggests an overcurrent condition (or DC condition if it is even checked), either true or just due to damaged protection circuits.
Something wrong with the PWM control loop may trip overcurrent, DC or HF protections (if they exist) as soon as the amplifier is un-muted. HIP pin 3 is gate drive enable.
But by the sound of point 5 in post #1 it seems that the amplifier shuts down as soon as it starts to switch, this suggests an overcurrent condition (or DC condition if it is even checked), either true or just due to damaged protection circuits.
Something wrong with the PWM control loop may trip overcurrent, DC or HF protections (if they exist) as soon as the amplifier is un-muted. HIP pin 3 is gate drive enable.
So, what we have now.
Bought some LM393s today and replaced all 3 of them in the amp. Now it even starts, so this replacement was not unsuccessful at all. After the first start found that at least one of the output mosfets was dead again. So soldered all 12 them out of board and put back only 4. But I've still got some new problems:
1. The amp still starts, but it draws about 2.5A already at 14V, or almost 10 Watts more than before the replacement. Those 4 output mosfets become really hot without heatsinking in few seconds.
2. It seems like internal relay switches on the load too soon, so if there is a load at the output, the amp starts to draw too much amps (much over 10A) without any sound at the output.
3. But if I wait for 2-3secs more after full start of the amp and only then connect the load, now it works better - still about the same 2.5Amps, but there is toooo much distortion at the output and almost no sound at all, when the current is still rising during the track.
4. Also there is some noise (like ticking, scratching, etc.) now coming from the power supply I think, and the higher the volume is, the louder this unlikely sound becomes.
And what could be the role of CD4013 in the amp? It is at least the last IC in DIP case that I also could replace...
Hope on your advices about what to do next.
Bought some LM393s today and replaced all 3 of them in the amp. Now it even starts, so this replacement was not unsuccessful at all. After the first start found that at least one of the output mosfets was dead again. So soldered all 12 them out of board and put back only 4. But I've still got some new problems:
1. The amp still starts, but it draws about 2.5A already at 14V, or almost 10 Watts more than before the replacement. Those 4 output mosfets become really hot without heatsinking in few seconds.
2. It seems like internal relay switches on the load too soon, so if there is a load at the output, the amp starts to draw too much amps (much over 10A) without any sound at the output.
3. But if I wait for 2-3secs more after full start of the amp and only then connect the load, now it works better - still about the same 2.5Amps, but there is toooo much distortion at the output and almost no sound at all, when the current is still rising during the track.
4. Also there is some noise (like ticking, scratching, etc.) now coming from the power supply I think, and the higher the volume is, the louder this unlikely sound becomes.
And what could be the role of CD4013 in the amp? It is at least the last IC in DIP case that I also could replace...
Hope on your advices about what to do next.
CD4013 is a flip flop. i don't think it has something to do with the audio part.
have looked the net for the service manual of this amp but without success.
have looked the net for the service manual of this amp but without success.
One more question about the ZD1: if I have only 3.83V there should I change it? Also there are about 4.1V on pin 6 and almost zero on pin 7. All these voltages were measured without the HIP (and it is probably dead). A couple of outputs were blown, so now I only use 4 of them for tests (IRF3710).
Note that the PWM could go through the CD4013. Audio usually goes through logic gates in class D amps.
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