any pic experts?

[smarbaga]

a six volt power supply is to high, the max is 5.5v.
use a 7805 regulator and make sure you have 5.1 volts

[posix]

OK Working now. When taking measurements I found an odd reading. 0.06v one side of a resistor (input to RA3) and 1.2v on the other side. Followed the trace and I found a teeny weeny short, hardly noticable by naked eye (is it possible that solder splashes?) between RS3 pin and OSC1 trace. Tip of the scalpel was enough to get rid of it and now it's all working 100%.

So I guess if your OSC1 is shorted to something your 16F628 doesn't work no matter whether you use the internal or external oscilator. Which shouldn't really be the case as OSC1 pin is used for I/O if you program the device with IntRC I/O, right?

[abasir]

On homemade PCB, shorts and breaks are normal occurence... I usually check the board with multimeter for trace continuity/break prior to soldering... Now, I'm planning to build a current tracer to pinpoint exact location of short/break for cases where the problem is hardly visible

Your RA3 is input (may be for STEP) and you configured OSC1 for IO (possible either high/low). Thus, your RA3 is stuck to a given level (either high/low) eventhough the PIC may be operating... no change in input, the PIC just stay put

[posix]

Now that you put it that way it's perfectly logical.