USB problem

[magolink]

Hello, the USB port on my Helix stopped working, apparently it was due to a PC overvoltage, does anyone have a diagram of the electronic part to see which component could have been damaged and see if I can repair it.

[craiganderton]

On 9/28/2023 at 9:26 PM, magolink said:

apparently it was due to a PC overvoltage

 

That seems unusual, unless you Helix got hit by lightning or there was a massive power surge capable of bypassing your power supply. So hopefully, it's one of the obvious USB issues:

 

• Defective cable
• USB cable that carries only power, not data. There's no way to tell the difference physically. I test cables by plugging into a phone and seeing if I can transfer files. If so, it handles data.
• If it's Windows, the USB ports haven't been set to stay on. You deal with this in device manager - expand Universal Serial Bus Controllers > right-click on each USB device or hub > if there's a power management tab, uncheck "Allow the computer to turn off this device to save power"
• Connecting to Helix through a USB port instead of a direct connection to the computer
• Switch to the USB port closest to the power supply, on the back of the computer

 

Maybe one of these will help. Good luck!

[Schmalle]

If it was indeed over-voltage check for defective TVS diodes (shorting).

Edit: no TVS diodes - just regular ones. See post below.

[CraigGT]

I have a Helix in a similar state and I've not seen any TVS diodes.

There are some passives on the IO board then it's cabled to the CPU board where I can find no continuity so I believe it's connected straight to the BGA processor chip.

 

Craig

[Schmalle]

This is the HX Stomp's USB input circuit. Test L6,L31 for continuity, C43,C47 for non-continuity and R58 for 221Ohm.

C40 had both sides on the same (ground) potential when I measured it - works regardless.

Helix should have some similar circuit on it.

Needless to mention to also check the four pins in the middle for continuity to the jack's contacts.

[CraigGT]

Here is the equivalent area from my Helix floor.

R349 is 220R, C38 and C316 are 220pF

I'm not sure if C8 is my problem or just not populated.

One side of C8 is USB ground.

[Schmalle]

On 10/2/2023 at 11:38 PM, CraigGT said:

Here is the equivalent area from my Helix floor.

R349 is 220R, C38 and C316 are 220pF

I'm not sure if C8 is my problem or just not populated.

One side of C8 is USB ground.

Stating the obvious here if you're somewhat knowledgeable in electronics :

Looks like the pin of the connector are +, data, data, -, shield from left to right. Test the right four pins of the connector for continuity to the jack's contacts. The left pin to C38 should measure 220Ohm and the other side of C38 should pass for continuity to the last jack' contact.

[CraigGT]

On 10/3/2023 at 12:04 AM, Schmalle said:

Stating the obvious here if you're somewhat knowledgeable in electronics :

Looks like the pin of the connector are +, data, data, -, shield from left to right. Test the right four pins of the connector for continuity to the jack's contacts. The left pin to C38 should measure 220Ohm and the other side of C38 should pass for continuity to the last jack' contact.

 

I traced it out and found similar except I see the ground to pin 5 and shield not connected to the header. Shield and ground have continuity through the MCU board if the header is plugged in.

The capacitor you said was grounded both sides and is missing on mine goes between ground and shield so that explains your measurements.

I can't find any continuity for the other side of L22.

 

Craig

[Schmalle]

On 10/3/2023 at 2:35 PM, CraigGT said:

I traced it out and found similar except I see the ground to pin 5 and shield not connected to the header. Shield and ground have continuity through the MCU board if the header is plugged in.

The capacitor you said was grounded both sides and is missing on mine goes between ground and shield so that explains your measurements.

I can't find any continuity for the other side of L22.

On the Stomp it's USB+ aka VBUS (USB socket) -> L6 -> R58 -> socket to processor board.

I can measure 220Ohm (R38) from the processor board to USB+ (USB socket).

 

On your image it looks like the the equivalent is USB+ -> L22 -> R349 -> 5pin connector.

You should be able to measure 220Ohm from red (or USB_VCC) to the left pin on the 5pin connector.

[CraigGT]

On 10/3/2023 at 3:35 PM, Schmalle said:

You should be able to measure 220Ohm from red (or USB_VCC) to the left pin on the 5pin connector.

 

On 10/3/2023 at 3:35 PM, Schmalle said:

On your image it looks like the the equivalent is USB+ -> L22 -> R349 -> 5pin connector.

You should be able to measure 220Ohm from red (or USB_VCC) to the left pin on the 5pin connector.

On a second look you are correct and I do get that 220 Ohm and continuity of the other usb pins too, apart from the screen. 

[Schmalle]

On 10/3/2023 at 5:12 PM, CraigGT said:

On a second look you are correct and I do get that 220 Ohm and continuity of the other usb pins too, apart from the screen. 

AFAICS that board should work then. I don't think that I can be of further help here.

[CraigGT]

Thanks for your effort and it pretty much confirms my thought that it's the processor board and there's not much that's replicable on there.

I was quoted around £400 for a repair, I ended up buying a new one wit three years warranty.

 

Craig

 

[Schmalle]

Is it

On 10/3/2023 at 9:54 PM, CraigGT said:

Thanks for your effort and it pretty much confirms my thought that it's the processor board and there's not much that's replicable on there.

I was quoted around £400 for a repair, I ended up buying a new one wit three years warranty.

Is it just the USB that isn't working?

[CraigGT]

Yes everything else works fine.