Focusrite Scarlett 2i2 gen1 repair

[tony359]

Hi all,

I have acquired a 2i2 USB sound card which came with a broken USB port. The pins were not mangled, the plastic stud was missing. I replaced it but Windows now sees something and shows a "Device Descriptor Request Failed" - which I believe it means "I see something but it's not telling me who they are"

I found the 2i4 schematics online, I feel the digital end is identical.

The USB goes through an USB 3343 IC which acts as interface with the host. Then it connects via ULPI protocol to the XMOS CPU, an ARM one which is connected to a small ATMEL memory IC where the firmware is stored I think.

3.3V and 1V voltages are ok. The CPU is not held in reset. I do see data being exchanged between the ATMEL and the XMOS. Clocks are there. Voltages are there.
There is NO activity on the ULPI lines though.

I de-soldered the ATMEL IC and dumped the content. It looks very similar to the 2i4 dump I found online (only the number of outputs change between the two cards). As an experiment, I programmed the IC with the 2i4 firmware - I was hoping it would show up under windows and maybe not working well, telling me the original FW was corrupted but no, same error.

USB data lines are ok and reach the USB3343 IC correctly.

I have ordered a replacement USB3343, I hope that the broken USB connector somehow contributed to the issue.

The original listing said the "power on" LED (which is the "USB recognised" LED) was "flashing on and off" when "plugged in" with the broken connector so I supposed the card has gone through a series of on/off sequences. Hence I was hoping the Firmware might have got corrupted.

Any ideas? Schematics of the 2i4 and a picture are attached. Thank you!

[прямо]

Not doubting your troubleshooting skill, but did you check if the USB3343 IC received power? as in, no shorted or dead capacitor on its supply pins?

[tony359]

No worries, I'm here to hear other people's ideas!

yes, I checked that the USB IC and the CPU were actually getting all the relevant voltages (the CPU has a few). All is well unfortunately.

[stj]

check the data path from the socket to the chip - and check L4

[CapLeaker]

Only that the USB IC is getting power, does not mean it is working o.k. For me I’d swap that out first.

[tony359]

Stj, data path is ok and also L4 - tested from solder joints under usb port to solder blobs around the IC itself.
CapLeaker - it’s already ordered indeed. Considering the card came with a broken usb port, I hope that’s the culprit!

thank you!

[tony359]

It was the USB IC indeed! At first it would not work but my soldering wasn't great - the IC is smaaaaall and I missed a pad! Once that was fixed, it now works like a charm!

[CapLeaker]

Awesome! Good job!

[tony359]

I made a video of the repair - and I've uploaded the Scarlett 2i2 and 2i4 firmware on this thread for future reference! Also the 2i4 schematics.

Let me know your comments! And thanks for the help!

[frankusb]

I like that video and enjoyed watching it. What is the clear gel you use for rework? Actually it would be interesting to me to know what other equipment was used as well if it's not too much to ask.

[tony359]

Thank you for your comment!
I should really make a list of the equipment and add it to the description of my videos.

Meanwhile, the "gel" is flux and it's needed when soldering. It prevents the solder from oxidising and makes it "flow". Without flux you cannot solder properly. I have some AMTECH - considered to be the best - but it's so expensive so I tested one from Aliexpress, it's called KINGBO RMA-218. I think it works well, at least for general soldering.
The hot air station is a Quick 861DE - similar to the more popular DW but with 200L/m maximum airflow.
The soldering station is a JBC CD-2BQF with a "knife" tip - which was too big indeed!
I was also using a pre-heating plate, it's not sold in the UK anymore because it was found to be dangerous as it was not grounded properly (I had to mod mine) but I'm sure they've released a "new" model. It's just a big BBQ plate to be honest! This one is called T-8280.

I've reviewed the pre-heating plate and the hot air station on my channel if you fancy a look

Thank you!

[rockamario]

I made a video of the repair - and I've uploaded the Scarlett 2i2 and 2i4 firmware on this thread for future reference! Also the 2i4 schematics.

Let me know your comments! And thanks for the help!

hi Tony can you give a link where I can buy this usb3343 ic? thanks in advance!

[прямо]

You can buy it from LCSC. I trust them better than Aliexpress.

https://www.lcsc.com/product-detail/...P_C633347.html

[tony359]

the store where I bought it is not available anymore - the 3343 is available from reputable sellers, I went to Ali because I wasn't sure I was going to fix it and didn't want to spend too much money on it. But the IC is still available online.