USB Client flashing red (when connected to mainboard)

Hello there,

my USB Client module is flashing red and getting extremely hot to the touch very quickly after power up. The heat seems to be contered on the “IC1”-component just right of the GHI “G”. It’s enough heat that one cannot touch that area. The mainboard’s program , as well as the attached modules (T35 display among them), do not start.

I power the USB Client via the usb port of my PC. It only happens when a mainboard is plugged in. I only have that one mainboard so can’t tell if it’s a mainboard issue.

If I power the USB Client via an external power source (at 8.35V) the flashing goes away but the LED is ‘dimming’ and there’s no activity from the mainboard.

I have tried to remove all attached modules, and have replaced the connectors to make sure a bad connector is not the issue.

Any thoughts on this? Thanks a lot in advance,


Hi Harley,

If i remember correctly, the red flashing on the DP module is an over-current warning.

What other devices do you have connected? That’s likely the cause, too many other modules drawing too much current to run safely. When you talk about removing them, did you leave them disconnected (ie DP module connected to mainboard only, and it connected to a PC?)

Hello Brett,

I did leave the modules disconnected, yes. There’s just the DP Module connected to the PC and to the Fez Spider mainboard :frowning: So why I’m getting an over-current warning is beyond me.

I could use the DP module for a toaster, 's how hot it gets.

Then I have nothing !

Things I’d be checking are whether it gets hot when it is NOT connected to anything else, and I’d be checking for shorts between any of the pins. If you have a multimeter, check for continuity between GND and both 5v and 3v3, perhaps there’s a bent pin in a connector?

Or, highly doubtful, but worth checking for solder joints.

Mine gets pretty warm as well at that point.

The only time I had issues like that (led blinking with the usb cable) was when my usb cable was being nudged up by another module and was on a slight up angle. I rearranged my devices on my board, and all was ok again.

@ harleydk - Just a thought, have you checked for any conductive “bits” that may have got trapped on the top and or bottom of the boards, bits i mean cut bits of wire or even solder splash from something else you have been working on. Is your work surface non-conductive?

@ harleydk - Does the USB DP LED blink even if you don’t connect it to the mainboard?
If you connect it to the mainboard only. Does it blink? Does the power LED lights up on the main board? Are you able to program it?

Hello everyone,

and thanks for your input - I’m very impressed with your speed in replying and commitment to this forum :slight_smile:

I’m running a solder-less desktop environment, so no issues with run-away solder. It’s a wooden desktop, by the way. I’ve checked the sockets, the pins are all straight as arrows, also I exchanged the connector cables, so shouldn’t be an issue here.

@ Joe It only happens when a mainboard is plugged in, if it’s the USB DP module only there’s no blinking. There’s no LED on the main board and I’m not able to program it :frowning:

I’m not the most prolific with a multimeter but I do have one and can check if there’s power flowing to the mainboard. Not really sure how I’d go about that but will check the schematics first thing when I’m back at work, and thus near the modules again, in the morning.

@ harleydk - The mainboard seems to withdraw more power than expected. Contact us directly to get an RMA number to send us the mainboard to check it for you. By the way, did the system work before? if Yes, at what point it stooped working?

Hello Joe,

the system worked perfectly up to the point where I plugged an external power adapter (a 12V 1000mA max wall wart, I measured the voltage at 8.35V) to the USB DP module. The system worked without problems, but switching back to running off the USB port was suddenly not possible, nor was it possible to then go back to the external power adapter again.

I’ll contact you directly - thanks for your support, so to speak.