Hi. I am repairing a DD Z2, which exploits the output transistors. only the 6 transistors left part near rectifier diode.
I have checked the output drive board and all good, replaced IR21844S as a precaution, but when connecting a speaker to the output, it explodes again the 6 transistors that I said previously.
What can happen?
Greetings.
I have checked the output drive board and all good, replaced IR21844S as a precaution, but when connecting a speaker to the output, it explodes again the 6 transistors that I said previously.
What can happen?
Greetings.
Does this one use the two-21844 driver board?
If you did not connect a speaker, did the amp produce an audio signal at the speaker terminals?
If you did not connect a speaker, did the amp produce an audio signal at the speaker terminals?
the drive board, has 4 units of 21844s. it did not emit any sound, only the transistors exploded.
After replacing the 21844 driver ICs, did you check the drive signals up to the gates of the FETs?
I could not measure the drive signal to the gates. How can I check the drive signal without having the output transistors installed on the board?.
I do not want to break more transistors...😀😀😀😀😀
I do not want to break more transistors...😀😀😀😀😀
Are all of the 2.2 ohm resistors within tolerance? R272A(?) looks like it got really hot.
Have you checked all of the small 47uH inductors. Some aare for the protection circuit and if one is open, the protection circuit may not function (and protect the FETs).
After the last FET failure, have you replaced all of the driver ICs?
After replacing them, did you compare the readings of all of them to determine if one was damaged when installing them?
You can pull the rectifiers and drive a strong signal into the amp (50-100Hz) and see if you get a good clean square wave at every FET gate leg.
Have you checked all of the small 47uH inductors. Some aare for the protection circuit and if one is open, the protection circuit may not function (and protect the FETs).
After the last FET failure, have you replaced all of the driver ICs?
After replacing them, did you compare the readings of all of them to determine if one was damaged when installing them?
You can pull the rectifiers and drive a strong signal into the amp (50-100Hz) and see if you get a good clean square wave at every FET gate leg.
Hello
I have solved the problem.
The problem was a resistance of 2.2 ohm 1W out of value.
It already works correctly.
Thanks for your help.
Greetings.
I have solved the problem.
The problem was a resistance of 2.2 ohm 1W out of value.
It already works correctly.
Thanks for your help.
Greetings.
Hello
I have had problems with the DD Z2 again. The output transistors have exploded again.
All these components are revised and correct:
R271-271A OK
R272-272A OK
R201, R186, R187 OK
Inductors OK (none open)
DRIVE BOARD:
4 IRS21844S new
TL072 and LM211 new
R44 and R36 OK
D5, D1, D6, D3 OK
The voltages 12v, +15, -15, +5, -5 are present.
Any idea what is happening?
Greetings.
I have had problems with the DD Z2 again. The output transistors have exploded again.
All these components are revised and correct:
R271-271A OK
R272-272A OK
R201, R186, R187 OK
Inductors OK (none open)
DRIVE BOARD:
4 IRS21844S new
TL072 and LM211 new
R44 and R36 OK
D5, D1, D6, D3 OK
The voltages 12v, +15, -15, +5, -5 are present.
Any idea what is happening?
Greetings.
Was it back in the vehicle and working normally when it failed? Or did it fail on the bench?
You stated that all of the listed components were good. Were they still intact after the last failure or have you replaced them after the last failure? If some failed, which ones?
You stated that all of the listed components were good. Were they still intact after the last failure or have you replaced them after the last failure? If some failed, which ones?
failed a test in the bank. it ran out of audio output. I turned off again, I heard a loud noise to static electricity and some output transistors exploded.
the components described above were checked before it failed again. Now I have to check all of them again. it is likely that IRS21844 from the failed side is in poor condition.
Do you know any way to check the output pulses of IRS21844 without having transistors connected to the board?
the components described above were checked before it failed again. Now I have to check all of them again. it is likely that IRS21844 from the failed side is in poor condition.
Do you know any way to check the output pulses of IRS21844 without having transistors connected to the board?
Remove the rectifiers and install the output transistors. Without rail voltage, they can't be easily damaged. Replace all known defective components (including any failed 21844s) and drive a sine wave of 50-100Hz into the amp. Check the signals on the gates of the output FETs. Having the FETs in the circuit loads the drive circuit and helps show any deficiencies.
You'll have to provide the high-side of the IC with a supply (9v battery works).
You'll have to provide the high-side of the IC with a supply (9v battery works).
When you post a waveform, you want the vertical amp set to show the waveform to span 3/4 of the display (from the reference line). You want the timebase set so you have 3-4 complete cycles.
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