I found the driver that the seller sent me for the CM6631A when I bought it a few years ago.
https://mega.nz/file/uAB0ECDY#DDgXyA9RtqLVJecjdmKb-8v7XNUwF0dF95NpAVMrbfA
I found this on Github:
https://github.com/highgain86j/audio_hw
https://mega.nz/file/uAB0ECDY#DDgXyA9RtqLVJecjdmKb-8v7XNUwF0dF95NpAVMrbfA
I found this on Github:
https://github.com/highgain86j/audio_hw
I found the culprit (actually me): Q22 right pin was not well soldered.
Now I have the following voltages:
TP1=4.86V
TP2=2.49V
TP3=1.66V
TP8=4.99V
TP6=6.09V
TP9=7.32V
TP10=6.09V
TP12=7.32V
@abraxalito Richard, Thank you for your prompt support.
Now I move forward to the next step.
Cheers.
Marco
Now I have the following voltages:
TP1=4.86V
TP2=2.49V
TP3=1.66V
TP8=4.99V
TP6=6.09V
TP9=7.32V
TP10=6.09V
TP12=7.32V
@abraxalito Richard, Thank you for your prompt support.
Now I move forward to the next step.
Cheers.
Marco
Hi Marco,
To better assess your soldering, clean the board in 90% Isopropyl alcohol and a soft bristle brush. I can’t be sure but looks like you have several places where cold solder joints can be giving you some issues.
Shouldn’t the values of C11 and C16 be much larger than Wima film caps will provide?
To better assess your soldering, clean the board in 90% Isopropyl alcohol and a soft bristle brush. I can’t be sure but looks like you have several places where cold solder joints can be giving you some issues.
Shouldn’t the values of C11 and C16 be much larger than Wima film caps will provide?
I understand the output capacitor could be a minimum of 4.7uF if no HP is used. I have asked @abraxalito
I have already cleaned and brushed the board with Isopropyl alcohol. I will do it again.
However previous measurement were ok right after the cleaning.
Marco
I have already cleaned and brushed the board with Isopropyl alcohol. I will do it again.
However previous measurement were ok right after the cleaning.
Marco
Marco - what I think likely has happened is putting the inductors in circuit has exposed an issue with the earlier soldered parts, those around the DAC chips.
Please measure the voltages on the TDA1387s pin6 and pin8. All pin6 are connected together, as are pin8 so you only need choose one chip to measure its pin6/8 voltages.
Please measure the voltages on the TDA1387s pin6 and pin8. All pin6 are connected together, as are pin8 so you only need choose one chip to measure its pin6/8 voltages.
Hi Richard, my Dorati was working perfectly until I started putting it into a nice enclosure and now I don't have any output on the left channel - I didn't suppose the enclosure was actually the problem so I've taken some measurements and would welcome your opinion. The fact that one channel is working correctly means that the digital front en is OK and the issue is likely to be in the analogue filter/output stage of the left channel.
Firstly the complete set of test point measurements:
TP1 - 4.9V
TP2 - 2.5V
TP3 - 1.7V
TP4 - 4.7V
TP6 - 6.0V
TP7 - 4.6V
TP8 - 5.0V
TP9 - 7.3V
TP10 - 5.9V
TP12 - 12.1V
All look OK except for TP12, which suggests the problem is with the final stage of the left channel output, so I took some more measurements and annotated the schematic as per attachment. The voltages in orange are for the left channel and those in green are for the right channel.
It looks as though the problem is around Q10, Q13. The soldering looks good and I can't see any bridges (and it worked previously) so I'm thinking a part replacement is required? what do you think?
Firstly the complete set of test point measurements:
TP1 - 4.9V
TP2 - 2.5V
TP3 - 1.7V
TP4 - 4.7V
TP6 - 6.0V
TP7 - 4.6V
TP8 - 5.0V
TP9 - 7.3V
TP10 - 5.9V
TP12 - 12.1V
All look OK except for TP12, which suggests the problem is with the final stage of the left channel output, so I took some more measurements and annotated the schematic as per attachment. The voltages in orange are for the left channel and those in green are for the right channel.
It looks as though the problem is around Q10, Q13. The soldering looks good and I can't see any bridges (and it worked previously) so I'm thinking a part replacement is required? what do you think?
Hi Ray - my suspicion falls on Q14, it maybe has failed. Check its base voltage (pin1 on schematic).
The measurement you have for Q14 emitter (pin2) looks improbable, its higher than Q9's emitter but there's no way to make it so high, other than a short on the PCB. Oh, it could be that your 11.18V measurement is in error, seeing you have two voltages for the same net. That the 11.18V is wrong would explain it.
The measurement you have for Q14 emitter (pin2) looks improbable, its higher than Q9's emitter but there's no way to make it so high, other than a short on the PCB. Oh, it could be that your 11.18V measurement is in error, seeing you have two voltages for the same net. That the 11.18V is wrong would explain it.
Hi again Richard. After some distractions I got back to the Dorati DAC today and have checked previous measurements and included some more - see the schematic below. As before, the voltages in orange are for the bad (left) channel and those in green are for the good (right) channel. I added some diagrams for Q9 and Q14 to keep the annotation clearer. Thoughts?
@abraxalito Hi Richard, I still need to troubleshoot my Doarati - any thoughts on my measurements in the previous post?