Hi!
Some weeks ago I completed my 7 channel amplifier based on three TPA3255 modules and one IRS2092 module. Each TPA3255 module has its own SMPS, as well as the IRS2092 module (see http://www.diyaudio.com/forums/class-d/87913-class-amp-photo-gallery-135.html#post5502488).
Upon completion I fired the amp up and everything seemed OK (all fault LEDs on the TPA3255 modules light up, which is the "normal" behavior for those modules, since they do not implement the corrent "fault LED circuit" described in the TI datasheets), and the green LED on the IRS2092 module also lights up.
All voltages are OK.
However, after I hooked up speakers and a source I found out that only the leftmost TPA3255 modules works, the other two do not produce any output at all. Same for the IRS2092 module.
In order to rule out a faulty wiring / protection module I deinstalled those speaker protection modules, the result is the same.
Any ideas on where to begin to look for faults?
Kind regards,
Arndt
Some weeks ago I completed my 7 channel amplifier based on three TPA3255 modules and one IRS2092 module. Each TPA3255 module has its own SMPS, as well as the IRS2092 module (see http://www.diyaudio.com/forums/class-d/87913-class-amp-photo-gallery-135.html#post5502488).
Upon completion I fired the amp up and everything seemed OK (all fault LEDs on the TPA3255 modules light up, which is the "normal" behavior for those modules, since they do not implement the corrent "fault LED circuit" described in the TI datasheets), and the green LED on the IRS2092 module also lights up.
All voltages are OK.
However, after I hooked up speakers and a source I found out that only the leftmost TPA3255 modules works, the other two do not produce any output at all. Same for the IRS2092 module.
In order to rule out a faulty wiring / protection module I deinstalled those speaker protection modules, the result is the same.
Any ideas on where to begin to look for faults?
Kind regards,
Arndt
I understand it such that you turned them all ON to see if you had the right lamps turning ON. After that you connected the speakers.
A class D amplifier should not run without load and you may have caused damage testing them without load.
I normally check the two outputs (per channel) to see if they may have shorted to either GND or Vdd using an Ohm-meter (test without power).
A class D amplifier should not run without load and you may have caused damage testing them without load.
I normally check the two outputs (per channel) to see if they may have shorted to either GND or Vdd using an Ohm-meter (test without power).
I know about the instable output off class-D w/o load, but never encountered problems firing them up without load.
TPA-32xx do a short circuit-check during power up. If there is one, you will notice the fault LED being active.
Yes, especially the TPA3255 should all work ok without a load (I only need five channels from the TPA3255, so one channel will always be without a load).
I cannot think of why swapping the supplies should change anything, since all voltages at the input of the amplifier boards read the same, but I will try anyway.
That still does not explain the IRS2092 board without any output. It fires up "ok", the built in speaker protection relay latches, but no output to the speakers. I will try bypassing the volume pot for that channel (all the others do not have one).
I cannot think of why swapping the supplies should change anything, since all voltages at the input of the amplifier boards read the same, but I will try anyway.
That still does not explain the IRS2092 board without any output. It fires up "ok", the built in speaker protection relay latches, but no output to the speakers. I will try bypassing the volume pot for that channel (all the others do not have one).
i mentoined that you swap the amp boards TPA3255 ....but anyway swaping the smps maybe clarify too
One error down...
The input on the IRS2092 module was shortened to ground...
Two more modules to go. But since my soldering station broke down I will wait for a replacement to arrive.
Another question: Every second or third time when I switch my amp on the circuit breaker of my flat cannot handle the inrush current and breaks down.
Is there an easy way to remedy that? For example with a module like this one: soft start or better this one: Soft start 2?
The input on the IRS2092 module was shortened to ground...
Two more modules to go. But since my soldering station broke down I will wait for a replacement to arrive.
Another question: Every second or third time when I switch my amp on the circuit breaker of my flat cannot handle the inrush current and breaks down.
Is there an easy way to remedy that? For example with a module like this one: soft start or better this one: Soft start 2?
Sadly two of the three TPA3255 boards are not working correctly.
I tried both boards with the SMPS of the correctly working module in order to rule out the SMPS as the culprit, but still no sound.
So I will have to disassemble everything in order to get a better access to the faulty modules.
Any recommendations on what to check? Taking off the heatsink and measuring voltages directly at the chip?
Anything I can do with my cheap DSO138 digital oscilloscope?
EDIT: Oh, and maybe I will take a closer look around all connection terminals, since I soldered my connector-pins directly into the holes left from unscrewing the speaker terminal connectors. Maybe I applied too much heat, and some SMD components suffered from it? Although I am pretty sure that I know how to solder correctly...
I tried both boards with the SMPS of the correctly working module in order to rule out the SMPS as the culprit, but still no sound.
So I will have to disassemble everything in order to get a better access to the faulty modules.
Any recommendations on what to check? Taking off the heatsink and measuring voltages directly at the chip?
Anything I can do with my cheap DSO138 digital oscilloscope?
EDIT: Oh, and maybe I will take a closer look around all connection terminals, since I soldered my connector-pins directly into the holes left from unscrewing the speaker terminal connectors. Maybe I applied too much heat, and some SMD components suffered from it? Although I am pretty sure that I know how to solder correctly...
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Hi
sorry the read this..
but if you disconnect every thing its a good start to check every board seperatly. mark the boards and make a check list what you have done.( i get crazy if i do not know what i have done at my 4 boards
)
voltages on the regulators
Voltage tpa chip
check output filter
is something getting war/hot?
all connectors and cables
frequence generator with 200mVrms and check the opamps and output signal (with differental probe)
sorry the read this..
but if you disconnect every thing its a good start to check every board seperatly. mark the boards and make a check list what you have done.( i get crazy if i do not know what i have done at my 4 boards
) voltages on the regulators
Voltage tpa chip
check output filter
is something getting war/hot?
all connectors and cables
frequence generator with 200mVrms and check the opamps and output signal (with differental probe)
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I have designed and built a few irs2092 amps. For some reason some power up with +17VDC on output if no load is connected.
The rest oscillate but cause the output filter to ring to many volts.
Either way I wouldn't fire them up now without a load connected.
You need to see if 2092 is oscillating first.
The rest oscillate but cause the output filter to ring to many volts.
Either way I wouldn't fire them up now without a load connected.
You need to see if 2092 is oscillating first.
I pulled those boards out from the case and seperated them.
One thing I did not think about prior to assembling my "stack" of amplifier boards:
The screw-holes on those boards have a ground connection. So by screwing them all together with metal rods (and attaching them to the bottom of the case) I connected all ground planes of the amplifiers together.
Would not be so bad if they were all using the same supply, but they don't.
Maybe that is what fried something?
And the working board was the first one I ordered, the second and third one were ordered from another seller. Maybe both were not working correctly from the start, who knows?
I just recently got a TAS5630 amplifier board (kind of the predecessor of the TPA3255), I will also cross check with that board.
@Nigel: The IRS2092 amp works fine now, the input was not wired correctly.
One thing I did not think about prior to assembling my "stack" of amplifier boards:
The screw-holes on those boards have a ground connection. So by screwing them all together with metal rods (and attaching them to the bottom of the case) I connected all ground planes of the amplifiers together.
Would not be so bad if they were all using the same supply, but they don't.
Maybe that is what fried something?
And the working board was the first one I ordered, the second and third one were ordered from another seller. Maybe both were not working correctly from the start, who knows?
I just recently got a TAS5630 amplifier board (kind of the predecessor of the TPA3255), I will also cross check with that board.
@Nigel: The IRS2092 amp works fine now, the input was not wired correctly.
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