I have a control board with a microcontroller in BGA package. I need now to measure a signal on some microcprocessor's output pin. The problem is that there is no test point around the microcontroller on the PCB. Does it exist any possibility how to get to the output pin without a test point? Thanks for any advice.
Does the control board have JTAG? JTAG offers "boundary scan", a way of determining each and every input and output pin on the chip - plus the values of internal registers and all sorts of other things. Of course, it means you need it connected to the JTAG chain, and a JTAG connector, and a JTAG probe, and software to drive it.
Otherwise, @ScottSeidman is right: you're out of luck.