AMB Laboratories DIY Audio

[peterotto]

Hi everyone.

I have built the y1 full++. When the unit gets plugged in via USB, switch goes on, but the CPU does not recognize the unit.
I checked all connections, twice. I researched other threads and no much info on CPU not seeing the unit. Right now, I am assuming I fried a circuit and it is not sending info back via USB.

Here are some measurements.

USB pin 1: 5.15V
USB pin 2: 2.86V
USB pin 3: 2.86V

U1U pin 2: 3.29V
U1U pin 3: 5.15V
U1U pin 9,10: 3.29V
U1U pin 12: 1.45V
U1U pin 13: 1.54V
U1U pin 14: 3.29V ????? <- strange.
U1U pin 15: 3.29V
U1U pin 21: 3.29V
U1U pin 22: 2.86V
U1U pin 23: 2.86V
U1U pin 24: 3.29V

U2U pin 1: 3.29V
U2U pin 2: 5.15V
U2U pin 4: 3.28V ????? -> seems odd to be so close to 3.29
U2U pin 5: 3.29V

U3U pin 1: 5.15V
U3U pin 3: 5.15V
U3U pin 4: 1.23V
U3U pin 5: 3.29V

J2U pin 1 (VBUS): 5.16V
J2U pin 2 (VCC): 5.15V


Thanks

[amb]

USB pin 1: 5.15V
USB pin 2: 2.86V
USB pin 3: 2.86V

This shows you have good 5V USB power.

Pins 2 and 3 are the data lines which carry pulses, and a DMM DC voltage measurement on them isn't really valid or meaningful.

U1U pin 2: 3.29V
U1U pin 3: 5.15V
U1U pin 9,10: 3.29V
U1U pin 12: 1.45V
U1U pin 13: 1.54V
U1U pin 14: 3.29V ????? <- strange.
U1U pin 15: 3.29V
U1U pin 21: 3.29V
U1U pin 22: 2.86V
U1U pin 23: 2.86V
U1U pin 24: 3.29V

All these look ok.

Pins 12 and 13 are the 12MHz crystal pulses, Pin 14 is unused, Pin 22 and 23 are the USB data lines again -- these voltages are meaningless.

U2U pin 1: 3.29V
U2U pin 2: 5.15V
U2U pin 4: 3.28V ????? -> seems odd to be so close to 3.29
U2U pin 5: 3.29V

These are all fine too. The difference at pin 4 is due to U2U's internal gate loss.

U3U pin 1: 5.15V
U3U pin 3: 5.15V
U3U pin 4: 1.23V
U3U pin 5: 3.29V

J2U pin 1 (VBUS): 5.16V
J2U pin 2 (VCC): 5.15V

All good too.

Despite this, I recommend that you reflow all the solder joints on U1U, U2U and J1U. Make sure the ICs are mounted in the correct orientation, and check the soldering by measuring the pin-to-pad resistance on both ICs as follows, you should have very close to zero ohms. Also inspect your work carefully for solder bridges.



If all that passes and it still doesn't work, then maybe U1U is damaged (e.g., static discharge or overheat from soldering).

[peterotto]

Unable to find any problems with the board through the multi-meter. I tried to remove the U1U and end up destroying the board. Better luck next time.

I bought a new board and parts just for the USB side. Made the connections and it worked. I went from sad to happy.
USB brings power, the switch turns from red to green when sound goes through. Yipee.

Now to the y2.

[peterotto]

scratch that.

I did work for a while. Then I went and replaced the jumper wires for pins, and that was the last of it. I found out the UD6 was blown. At this point I have no idea what the problem is. Very frustrating.

[amb]

How did you deduce that U6D is blown? And since it was working until you started mucking with it, then that probably was the cause. Something got shorted while the power is live?

If you're sure it's U6D, then replace it.

[peterotto]

I checked the voltage at the 4.75v point. It wasn't there, so I back tracked through the schematic to the U6D and found it's values wrong. Replaced U6D; now every voltage is back to the correct value again. Then I went searching on other forums to find what are the causes of DAC not being recognized. What I gathered it is a "static discharge". With what parts I had, I replace the U2U and U3U with no avail. Looks like I will have to replace the dreaded U1U to see if that does the trick. That part is on order.

[dsolodov]

You could try to reflow U1U. I did that by pulling the hot iron accross the pins and then using wick to remove extra solder. Then I spent time to check each pin using a) magnifying glass and b) DMM as in AMB's post above. Before solding y1, I got a practice kit for SMD soldering and tried it.

[peterotto]

RE-built gamma1. Still didn't work. Tried this tried that. I just don't believe there was a static discharge or my soldering sucked.
Found an extra cable laying around, used that and it works again. How often does that happen! What a PITA!

Stupid Window 7 32bit took some work to get the driver installed. Then it decided not to work. The other PC with a 64 bit version had no issues.

Now to gamma2.

[amb]

A wonky cable could indeed cause you grief.