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γ3 - Strange problem after 1 year of work

gamma3, gamma24 (plug-in for the γ3)

γ3 - Strange problem after 1 year of work

Postby daniele86 » December 9th, 2016, 1:58 am

Hi guys,
I've a problem with my γ3 dac. The dac work very well until yesterday when it start to have this problem. I play music from my pc using the usb input of z1.

There are some "scratch" during song, this scratch appear sometime . I try to see if there is some "connection" between the problem and the type of file that I play. The only thing that I see is that at 44khz and 48khz the scratch is rare, with higher sample rate and higher bit rate It occurs most frequently and it's impossible to listen the song (in particular with 192khz music, is like play a song from a bad radio signal).

I made the prototype board, and I didn't follow the step of the initial check of γ3; but this morning I made all the point, and nothing is wrong except this: 0Ω between G (backplane) and chassis (DAC). I have infinite resistence. Everything else is ok.

This evening I'm going to use my WaveIO board and put the signal into coaxial input (i try from TV with optical cable and it seems ok, but the signal is 44khz and I can't try different sample rate).

What it could be?

thanks a lot
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Re: γ3 - Strange problem after 1 year of work

Postby daniele86 » December 9th, 2016, 4:15 am

I have one good news! from coaxial input (with WaveIO) everthing is ok!

So i think the problem is in the audio witdget module or some parts for usb input (or also something on the i2s path). Is there the possibility that a high umidity (I don't know how much) in my room (kitchen) cause some problem?

I also tried with usb from udoo quad board with volumio and I have the same problem.
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Re: γ3 - Strange problem after 1 year of work

Postby amb » December 9th, 2016, 11:24 pm

Are you using the same USB cable for each case? If so try changing to a different cable.
If that doesn't make a difference, gently remove and re-seat the ζ1 Audio Widget module to rule out any electrical contact problem.
If that still doesn't fix it, maybe some parts on the backplane board need to have their solder joints reflowed.
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Re: γ3 - Strange problem after 1 year of work

Postby daniele86 » December 10th, 2016, 12:10 am

I already tried with different usb cable with the same result.
I also remove and reseat z1 module.
I'm going to reflow some solder joints. In order, which parts I should check?

Inviato dal mio LG-D802 utilizzando Tapatalk
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Re: γ3 - Strange problem after 1 year of work

Postby amb » December 10th, 2016, 12:28 am

The two oscillators and the small SOT-23 logic parts on the backplane under the ζ1, the digital isolator U15, and maybe some of the board connector pins/receptables.
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Re: γ3 - Strange problem after 1 year of work

Postby daniele86 » December 29th, 2016, 3:24 am

I've just reflow all the parts concerning Z1 module: X1, X2, U17, U18, U15, Q1, Q2 with no result. The dac work like before, with the same problem.

Because the problem is only with USB input, I think is not necessary reflow or check some y24 parts, it's correct? What can I do?

Thanks
Daniele
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γ3 - Strange problem after 1 year of work

Postby amb » December 29th, 2016, 8:57 am

Try reflowing U12 and U13 on the backplane too. These are the I2S lines from the ζ1 to the γ24, and the DSD contriol line from the LCDuino-1 to the γ24 (not used at the moment, but should be logic "low"),

If this doesnt fix the problem, then inspect/reflow the I2S lines on the γ24 to U1 pins 46, 47 and 48 (see γ24 schematic).

If this still doesn't work, then maybe the ζ1 is faulty. Does the UAC LED light up? Does it change color appropriately when switching between UAC1 and UAC2 modes?
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Re: γ3 - Strange problem after 1 year of work

Postby daniele86 » January 14th, 2017, 8:46 am

Hi Ti,
A week ago I reflowed some parts, but stupidly I forgotten which ones. :roll: After that, the dac work worst than before.
Today I start to reflow few parts for one time: U12 - U13, with no result. Then i2s pin signal on SRC and U15, and is the same (the dac now work worst than 1 week ago).

I see that, also with NO usb cable on input, the frequency on lcduino appear and disappear, with UAC1 and UAC2.
I think the UAC led is working good.

I think the problem is in the z1 module or its below parts (U17, X1, X2..) :?:

what can I check?

I have some few spare parts that i can change:
y24 : U4 - U11 - U5 - U9 - U10 - U11
y3 : U16 - U20 - U17 - U18 - U10 - Q1 - Q2 - U2 - U4 - U6 - U8 - U19
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Re: γ3 - Strange problem after 1 year of work

Postby amb » January 14th, 2017, 11:51 pm

daniele86 wrote:A week ago I reflowed some parts, but stupidly I forgotten which ones. :roll: After that, the dac work worst than before.

If the behavior changes with the reflow, then the reflow had changed something. Hopefully not damaged from overheating...

I see that, also with NO usb cable on input, the frequency on lcduino appear and disappear, with UAC1 and UAC2.
I think the UAC led is working good.

When no USB cable is attached then the sample rate is indeterminate. However, it usually defaults to 48KHz after power-on.

I think the problem is in the z1 module or its below parts (U17, X1, X2..) :?:

what can I check?

I have some few spare parts that i can change:
y24 : U4 - U11 - U5 - U9 - U10 - U11
y3 : U16 - U20 - U17 - U18 - U10 - Q1 - Q2 - U2 - U4 - U6 - U8 - U19

Exaine/measure solder joints on all these before attempting to replace anything parts.

- If the system works with S/PDIF (coaxial or optical) sources then it's unlikely to be any problem on the γ24, except the I2S lines from the ζ1 to the γ24, including the digital isolator U15.
- You should get about 3.3V at the VREF test point (relative to IG) when power is on. If this is ok, then U16 is good.
- If you get 5V (relatve to G) at ζ1's ZVDD_5V0, then U20 is good.
- Measure the voltage at γ3 U17 pin 4. It should be 3.3V when playing 44.1KHz (or multiple of that) program material, or 0V when playing 48KHz (or multiple). If that's true, then U17 is good.
- It's a bit difficult to test γ3 U18 unless you have a oscilloscope. The output should be half the frequency of the input (i.e., if input is 22.8792MHz then output should be 11.4396MHz. If the input is 24.586MHz then the output should be 12.288MHz).
- If you're using TORX147PL and TOTX147PL optical receivers and transceiver, and if your jumper configuration is correct, then you should measure 3.3V at the VRXTX test point (relatve to IG). If this is ok, then γ3 U10 is good. If your optical inputs/outputs work, then this has to be true.
- γ3 U2, U4, U6 and U8 should not be populated if you are using TORX147PL and TOTX147PL (see parts list configuration matrix).
- γ3 Q1 and Q2 is only used for changing UAC mode, so if that appears to work then don't replace them.
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Re: γ3 - Strange problem after 1 year of work

Postby daniele86 » January 15th, 2017, 1:52 am

amb wrote:If the behavior changes wwith the reflow, then the regflow had changed something. Hopefully not damaged from overheating...

I hope too, I have new solder station; which is the correct solder temperature for smd parts? I set it at 330 degree.
The problem could be also some connector pins, reflowing under z1 I removed z1 module more times

When no USB cable is attached then the sample rate is indeterminate. However, it usually defaults to 48KHz after power-on.

Yes but also with usb cable attached and playing music the display don't show a fixed sample rate (appear and disappear)


Exaine/measure solder joints on all these before attempting to replace anything parts.

- If the system works with S/PDIF (coaxial or optical) sources then it's unlikely to be any problem on the γ24, except the I2S lines from the ζ1 to the γ24, including the digital isolator U15.

Yes Confirmed

- You should get about 3.3V at the VREF test point (relative to IG) when power is on. If this is ok, then U16 is good.

3,4V (is a little higher - it always has been so)

- If you get 5V (relatve to G) at ζ1's ZVDD_5V0, then U20 is good.

5.05V

- Measure the voltage at γ3 U17 pin 4. It should be 3.3V when playing 44.1KHz (or multiple of that) program material, or 0V when playing 48KHz (or multiple). If that's true, then U17 is good.

It's a bit difficult to check because is under z1 module. I'm going to put a wire for check this, I have some doubt about U17, because I have prototype board and I made a (bad??) bridge between U17 pin4 and X1 pin1.

- It's a bit difficult to test γ3 U18 unless you have a oscilloscope. The output should be half the frequency of the input (i.e., if input is 22.8792MHz then output should be 11.4396MHz. If the input is 24.586MHz then the output should be 12.288MHz).

I haven't :cry:

- If you're using TORX147PL and TOTX147PL optical receivers and transceiver, and if your jumper configuration is correct, then you should measure 3.3V at the VRXTX test point (relatve to IG). If this is ok, then γ3 U10 is good. If your optical inputs/outputs work, then this has to be true.

3.289V

- γ3 U2, U4, U6 and U8 should not be populated if you are using TORX147PL and TOTX147PL (see parts list configuration matrix).

sorry yes

- γ3 Q1 and Q2 is only used for changing UAC mode, so if that appears to work then don't replace them.
yes
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