Got me a PICkit2 programmer clone and a SOIC8 test clip from the good people at banggood. If you intend to use linux as your programming environment - get the PICkit2, NOT the PCIkit3. There is no linux driver for PICkit3.

I'm currently setting pk2cmd up on my Ubuntu machine, following http://iam-saminda.blogspot.co.nz/2015/03/chipset-programming-with-linux-1-pickit.html and http://hackaday.com/2010/11/03/how-to-program-pics-using-linux/

$ sudo apt-get install build-essential libusb-dev

Download the PICkit2 driver source. It doesn't seem to be hosted by microchip any more, but it is on sourceforge. https://sourceforge.net/projects/pic-linux/

untar the source and cd into the directory.

$ cd pk2cmdv1.20LinuxMacSource
$ make linux
$ sudo make install

Check that it installed (with the pickit2 plugged in):

$ pk2cmd -?V
Executable Version:    1.20.00
Device File Version:   1.55.00
OS Firmware Version:   2.32.00
Operation Succeeded

The PICkit2 was surprisingly simple to setup. The only hiccup I encountered is to tell pk2cmd where to find the PK2DeviceFile.dat file. Specify the directory containing it with -B/usr/share/pk2/ or put it in your PATH or current directory.

Now we need to plug the programmer onto the chip.

Find the pinout of the PICkit2 on page 9 of its datasheet.
http://ww1.microchip.com/downloads/en/DeviceDoc/51553E.pdf

I wrote the signal names on the back so that info is always where it needs to be.

Match it to the pinout of the PIC12 series, and wire accordingly. My best guess for the device is a PIC12F510, but the whole PIC12 series should have very similar pinouts for the programming pins. The PIC12F510 datasheet has pinout on page 2. http://ww1.microchip.com/downloads/en/DeviceDoc/41268D.pdf

We've got to prepare the servo PCB a little for in circuit programming.

1. Detach the hot glue holding the resonator, and carefully bend it out of the way.
2. Get rid of the excess solder between the cap and pin 8 so the clip will fit.

Trim the sides of the test clip so that it fits between the gaps of the other components (regulator, cap and resistor). Attach the test clip snugly.

(First time I did this, I just soldered wires to the appropriate pins).

Now for the moment of truth ... to ask it what the chip is on the other end (remember we don't know even if it is a PIC at all yet), ... drum roll please ..., No, then just blink the LEDs on the programmer then ...

$ pk2cmd -B/usr/share/pk2/ -P
Auto-Detect: No known part found.

Ah NO! Fail. What's wrong?

I reseat the soic8 test clip two dozen times. Trim it some more. Bend the pins inward so they make better contact. Still no luck. So I start desoldering bits:

• The resonator - maybe the factory program is starting up before the programmer can get it into programming mode.
• The potentiometer input - maybe it is providing too much load on the program data pin.
• A capacitor connected to the program data pin - maybe it is loading the pin with too much capacitance. A bit of RC time constant action reducing the slew rate.

Success!

$ pk2cmd -B/usr/share/pk2/ -P
Auto-Detect: Found part PIC12F675.

Our device is a PIC12F675! http://www.microchip.com/wwwproducts/Devices.aspx?product=PIC12F675

So we need to remove the capacitor attached to pin 7 of the PIC. It is affecting the slew rate on PGD/ICSPDAT signal from the PIC. This was its purpose of course - to be a low-pass anti-aliasing/noise reducing filter for the potentiometer input, but it does its job too well for in-circuit programming.

That's the capacitor in conflict. We should replace it after we are done reprogramming the PIC12F675.