[Terry_VK5TM]

UP2819 - is pin 7 high or putting out a pulse train (high = pll locked other = unlocked)

And is the 5.76MHz xtal working (pins 2 & 3).

And the obvious one (measured on the actual IC pins) - +5V (Pin 1) and GND (Pin 13)?

Is it receiving data from the MCU ? Pin16 = CLOCK, Pin 17 = DATA & Pin 18 = LATCH <- should be a positive pulse at the end of the word transfer.

Edit: There are also a lot of very low value electrolytic caps around the PLL ic and tuning voltage buffer that I would be suspicious of as well.