STLINK-V3PWR quality control

[JakaBac]

Hello,

The QC for STLINK-V3PWR assembled in France seems to be very bad. I received a unit that doesn't work out of the box (when USB is connected the status leds stay off, AUX power outputs 3.3V, host computer doesn't detect V3PWR).

The same host computer works just fine with another V3PWR unit. 

I decided to check the faulty unit out to see if there is a trivial fix for the issue (since the return shipping to the distributor is quite expensive). I found out that the USB3340 constantly has RESETB signal low, since it also has VCCIO applied this means that it is effectively disabled and tristated. Trying to trace where RESETB goes, I found U35 on the other side partially lifted, underneath U35 there was a small SMD resistor propping it up. I don't know how this could have passed QC.

Reworking U35 unfortunately did not improve anything. Unfortunately there are not schematics available for the V3PWR to make such troubleshooting easier. U35 seems to be a dual op-amp.... 

Is there any chance to get the schematics of STLINK-V3PWR? Or at least information what controls the RESETB signal on the V3PWR's USB PHY?

Thanks! 

[Simon V.]

Hello,

STLINK-V3PWR has an important quality check flow like other STLINK which include several programming and electrical tests. It is very strange that a product out of the box doesn't power on. Let me see internally how we can manage this non working unit you received.

Regards, 

Simon

[JakaBac]

Hi Simon,

Thank you for looking into my issue. If you need any details about the non working V3PWR please let me know.

Best Regards,

Jaka

[JakaBac]

Hi Simon,

Farnell decided that they will organize a pickup of the faulty V3PWR and provide a refund. In the meantime I already ordered another one from them.

But apparently my faulty one slipped through the QC process. The pick & place machine apparently messed up with the resistor that somehow got stuck/dropped under U35 and nobody tested the USB connectivity during QC. I imagine that somebody needs to plug it manually if USB connectivity is tested with the USB-C connector mounted.....

Best Regards,

Jaka

[Simon V.]

Hello,

Could you please share the serial number of the faulty V3PWR ? Thanks in advance for your help. Regards, Simon

[j-claude]

Hello,

the board serial number is not directly visible, you have to scan the QRCore on the bottom side of the PCB. Please share the information of this QRCode.

Normally, all boards are functionally tested by our EMS. This kind of issue should not appear!

Best Regards

[JakaBac]

Hi,

Unfortunately I already sent the faulty unit back to Farnell since they offered to provide UPS collect service. 

If it helps their RMA reference is 3361422 and the case reference is 10950152. Looking at UPS tracking info I can see that they already received the faulty unit.

I'll reply to the case asking them if they can provide that info

Best Regards, Jaka