Can't get this thing to oscillate.I'm assuming I have defective parts on the 3s driver board,they all test fine in circuit.Will work on that in a bit.
Question is,the waveform in the picture is what I'm getting on only one pin entering driver board.I'm assuming its coming from the ic's in the grey box?It will only manufacture the square wave if there is an input signal.
Does this waveform prove the ic's in the box are working properly?
Am I to only have one square wave entering the driver board?
Question is,the waveform in the picture is what I'm getting on only one pin entering driver board.I'm assuming its coming from the ic's in the grey box?It will only manufacture the square wave if there is an input signal.
Does this waveform prove the ic's in the box are working properly?
Am I to only have one square wave entering the driver board?
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Did you test it with all outputs and an intact driver board in the amp?
No. Having the square wave pass through the module isn't a guarantee that the module is working properly.
No. Having the square wave pass through the module isn't a guarantee that the module is working properly.
The squarewave is with driver board removed.Amp originally went into protect.Removed driver board and found one shorted 2sa1797.Replaced that and reinstalled the board.Still no oscillation.All voltages are confirmed(5,12,15 and rail).Then all of sudden it dived into intense current draw.Good thing I had a 2 ohmR inline along with power supply set to limit current.Removed board and checked voltages on all driver board pins.
The left set of pins have identical voltages as right side.The center pins(one)is where the square wave is fed from.
At this point have found no shorted components on driver board.I would assume change all 1d and 2d's.Look like they got pretty hot.Although all junctions test okay.
The left set of pins have identical voltages as right side.The center pins(one)is where the square wave is fed from.
At this point have found no shorted components on driver board.I would assume change all 1d and 2d's.Look like they got pretty hot.Although all junctions test okay.
Perry,trying to learn how this thing works....
There's 5 pins on bottom of grey box.+/- 5vdc,ground.Audio in and square wave out.
I would assume that all is well ?Square wave from grey box is sent to the 1d and 2d drivers.
There's 5 pins on bottom of grey box.+/- 5vdc,ground.Audio in and square wave out.
I would assume that all is well ?Square wave from grey box is sent to the 1d and 2d drivers.
Beware!! These type of amps end up with failed solder joints at the grey box.Im sure this is common.And can not be seen with magnifying glass.By wiggling it cured the oscillation issue.Also,one inductor almost fell out because of shotty soldering.
Is the amp not working properly?
Did you pull the module to confirm that there were no broken legs?
There have been instances (or at least 1 instance) where a problem with a capacitor on the board in that module caused problems with normal, high frequency, oscillation.
Did you pull the module to confirm that there were no broken legs?
There have been instances (or at least 1 instance) where a problem with a capacitor on the board in that module caused problems with normal, high frequency, oscillation.
As I was checking waveforms with driver board removed all seemed okay.I left and came back,no waveform.Cycled the power supply and square wave came back.
As I'm sitting there watching the scope,the waveform appears then dissappears.
So I started wiggling things.Noticed when I wiggled the grey box I can make the signal bounce on the scope.I did this for a solid 5 minutes.Desoldered and removed grey box after inspection with a mag glass.
Reinstalled the grey box and no matter what I did,the waveform was consistent.
Resintalled the driver board and now I do have oscillation.All seems well.
Turned the amp over,output inductor almost fell out.One leg completely fell out of solder joint and the other would wobble.
This this really is a poor made piece of s#@+.
Also did find two c3198 transistors with all legs "open" in preamp section.This was prior to the oscillation issue.
I'm probably going to go over every single solder joint that looks even half questionable.
As I'm sitting there watching the scope,the waveform appears then dissappears.
So I started wiggling things.Noticed when I wiggled the grey box I can make the signal bounce on the scope.I did this for a solid 5 minutes.Desoldered and removed grey box after inspection with a mag glass.
Reinstalled the grey box and no matter what I did,the waveform was consistent.
Resintalled the driver board and now I do have oscillation.All seems well.
Turned the amp over,output inductor almost fell out.One leg completely fell out of solder joint and the other would wobble.
This this really is a poor made piece of s#@+.
Also did find two c3198 transistors with all legs "open" in preamp section.This was prior to the oscillation issue.
I'm probably going to go over every single solder joint that looks even half questionable.
Well.....during testing the drive signal was lost again.The shotty connection is definitely inside this little box.I'm sure its gonna be a pain getting all this epoxy off to find a bad connection.What's the chances of making a new board?I'm assuming there's two ic's and capacitors etc in there.Not to many components.
Audio in,5 volt in and square wave out.
Obviously there's some important things to consider.Frequency etc.Any ideas?
Audio in,5 volt in and square wave out.
Obviously there's some important things to consider.Frequency etc.Any ideas?
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I got almost all of it off in 5 minutes actually lol.One little section is giving me fits.Trying to burn out the rest with soldering iron.One resistor and ic broke off.I found them luckily!!
Also found smd transistor marked 2A7? I think its PNP and this is a low voltage situation.
Use mmbta 56?Its the transistor in top right corner in photo.
Use mmbta 56?Its the transistor in top right corner in photo.
Of coarse I don't have those lol.I'm guessing the ic's are 211/072.How do I know which goes where?
I'm assuming you mean audio signal correct?If so,piece of cake.I'm sure they were not bad.But one got removed with the epoxy.That one little transistor for all this work lol.
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