TLC5940 DCPRG to 5v Stopping driver from working?

Hi All I'm currently working on a project using 2xTLC5940s with an 8x4 Grid. Everything's going fine at the minute as I solder up the LED strips and get everything ready to move off the breadboard. One thing that has caused me issue a couple of times is following the recommended wiring guide and having Pin19 (DCPRG) connected to +5v. When i do this the TLC only seems to sink the Ch0, though it seems to be following the correct timing for the sketch. When I disconnect Pin19 entirely everything works as it should. Could I have VPRG connected incorrectly to GND or is something else amiss? I'll take some pics tonight in case anyone can identify where I'm going wrong.