Fixing my partial dead Class D IRS2092

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Hi, I'm Andrew, this is my first post

So, I made this amp from a chinese Class D amp module, that utilize an IRS2092 and a IRFI4019, the power comes from two SMPS of 48V each one, to make +/-48V. I've been using it for almost a year, this is a stereo amp, but I only have one subwoofer, so I just using the left channel (at that time the right and left channel works just fine). The other day I got another subwoofer, so I tried to connect to the right channel and bang, all the negative rail directly to subwoofer, immediately turn it off.

Disassembly all the amp, and one of the mosfet was shorted, so I replaced it with a new one, I thought that would solve the ploblem, but not, all the negative rail again directly to now a 8 ohm dummy load :(. I found that the diode above the mosfets was shorted too, so I replaced with a new one (I have another dead amp like this for parts, this one came bad from China).

Then, I connected it again and the negative rail to the output disappear, but to my suprise there was no audio, the left channel is intact, just the right channel is the faulty one.

I started to check voltage all around the IRS2092 and this is what I found:

  • The 15v zener diode only gives 1.5V or so, when it is turn on.
  • On pin 4 the good channel gives me on the multimeter around 700kHz, and the bad one just steady 5.6V. With no audio on the input and no load in the output.
  • The J31C on the left of the mosfet in diode mode on the DMM, the negative lead of the DMM to base and the positve lead to emitter show 2.6 drop voltage on the good channel and 0.6 on the bad channel.(I tried to make a schematic but maybe it is wrong)
  • I realize almost of the didos cheking it in reversed bias, in diode mode give 2.6V, i do not know why.

Well, that is all that I found out at all. I don't know what to do :confused:, so, that is why I'm here (I attached a imgur album of the amp). I hope that someone of you can help me. I don't want to buy a new one. Thanks in advance :)

Class D Amp - Album on Imgur
 
Last edited:
Hi, I'm Andrew, this is my first post

So, I made this amp from a chinese Class D amp module, that utilize an IRS2092 and a IRFI4019, the power comes from two SMPS of 48V each one, to make +/-48V. I've been using it for almost a year, this is a stereo amp, but I only have one subwoofer, so I just using the left channel (at that time the right and left channel works just fine). The other day I got another subwoofer, so I tried to connect to the right channel and bang, all the negative rail directly to subwoofer, immediately turn it off.

Disassembly all the amp, and one of the mosfet was shorted, so I replaced it with a new one, I thought that would solve the ploblem, but not, all the negative rail again directly to now a 8 ohm dummy load :(. I found that the diode above the mosfets was shorted too, so I replaced with a new one (I have another dead amp like this for parts, this one came bad from China).

Then, I connected it again and the negative rail to the output disappear, but to my suprise there was no audio, the left channel is intact, just the right channel is the faulty one.

I started to check voltage all around the IRS2092 and this is what I found:

  • The 15v zener diode only gives 1.5V or so, when it is turn on.
  • On pin 4 the good channel gives me on the multimeter around 700kHz, and the bad one just steady 5.6V. With no audio on the input and no load in the output.
  • The J31C on the left of the mosfet in diode mode on the DMM, the negative lead of the DMM to base and the positve lead to emitter show 2.6 drop voltage on the good channel and 0.6 on the bad channel.(I tried to make a schematic but maybe it is wrong)
  • I realize almost of the didos cheking it in reversed bias, in diode mode give 2.6V, i do not know why.

Well, that is all that I found out at all. I don't know what to do :confused:, so, that is why I'm here (I attached a imgur album of the amp). I hope that someone of you can help me. I don't want to buy a new one. Thanks in advance :)

Class D Amp - Album on Imgur

Change irs2092 and mosfet all at the same time.
 
So yeah, I managed to fix it, I found another diode shorted and apparently the IRS2092 that I replaced was also dead :usd:, so i found another used one lying around, replaced and work like a charm!!!! :yikes:. So, thank you for your replies :)

Pleased to hear you got it fixed.
I usually use PDIP 2092's but they are getting to be a struggle to find.
The SMD version still seems to be plentiful.
Another tip is not to attach/detach scope probes on the 2092 while it is turned on. I have blown a couple doing that.
I attach the scope probe while the power is off then turn it on.
 
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