Can anybody help this newby please.
I have studied a few datasheets and other docs, forums and FAQ's, but I just end up with more questions than answers.

I get from a Microchip document that the 12V VPP is supposed to be some kind of pulse.
Now assuming that the 5V VDD is a continuous smooth voltage (and I am not sure), how can the DIY programmers that are posted all over the web, draw these two voltages from the same comms pin?

I tried to program a PIC16F690 with the simple "walk.hex" but while the chip verifies OK, it will not program. I think it has to do with the power supplies.
When I try to read, I get "Read error or chip empty". It is a new chip, but should it not at least read the device ID from memory?

I get power from the serial pin 3:
Via 4.7 K to VPP
Via 7805 IC to VDD with 10uF on chip side and .22uF on computer side.

I will probably end up buying an entry level programmer from RS , but I would like to play around a bit first.