Need help fixing my x0x

[tempomaster]

I recently bought a used x0xb0x that arrived dead. It appears to be an original adafruit x0x. At least the pcb looks identical to the one in my official adafruit x0x.

I touched up a bunch of solder joints (didn't find anything bridged) and put in my original adafruit (from my other kit) and it works mostly.

Problems:
The mode knob appears to do nothing in the following positions:
User B
User C
Bootload
Computer Control

My computer can see the USB chip, but does not see the x0xb0x.

Any thoughts on this? Where do I go from here?

[SubStyler]

I would start with checking the microcontroller and then the Mode switch.
check the Mode switch for the right position... pull the knob and check the shaft position of the switch. if the flat side on the shaft points down, the x0x is in Sync Out mode.
the switch can also be broken or the diodes on the MLB. (check D1-D4)

cheers

[antto]

the x0xb0x normally doesn't do anything in USER B, USER C, COMPUTER CONTROL, BOOTLOAD
so if the other modes work - it's fine

as for the usb, if it pops up in the OS as a usb device - it works, you need to get the usb-serial driver installed