Quote Originally Posted by Darrel Taylor View Post
What value capacitor do you have on Vusb (pin 18)?

Are you powering the PIC from the USB power or External power?

I've never seen 22 ohm resistors used before. Normally it's direct wired to the pin.

the capacitor on Vusb is 100nF

the power comes from an external source, and as said, it works just fine without the USB...

the 22 ohm resistors are only to give a small additional protection, they should not be harmful for the real work... There is also a SN65220DVB circuit swallowing bigger voltages, for real transient high voltage protection.
Why use condoms if you are sure?