Below are the schematics useful for debugging and understanding function

IRPS – Note the capacitor isn’t required

Input board

The schematic is broken into two diagrams, with the right side of the first diagram meant to join onto the left side of the second diagram

Output board

The protection function
Various Connectors
Strobe driver
MOSFETs and driver

4 thoughts on “PPA – schematics”

    1. Dan,

      Thanks for posting the schematics, and I’ve also stumbled across the PPA debugging, powering up and commissioning posts. These are all helpful as my PPA is not working [heavy sigh].

      No horrible smells or hot components, I’m seeing the second from the end LED of BAR1 on, a current of about 170mA, and a blank screen, so not far from success, probably some wrong connections between boards, IRPS, and EMs.

      I do have three 300 ohm resistors left over. A little worrying but have double and tripled checked instructions.

      1. Hi Geoff,
        thanks for the update, looks like you’re leading the race to get your PPA up and running. A blank screen indicates attention needed on the Arduino/Input board side of things. Check all the input and output board pins are firmly plugging down into the Arduino, which means looking at the boards from underneath (difficult to do with all the EM’s and IRPS’ wired up).
        Don’t worry about the leftover 300ohm resistors, the packing process had some challenges which were most economically addressed by simply including additional parts (it’s a long story, don’t ask!).
        Do you have an oscilloscope? If not, keep in mind also that the sockets on the top of the Arduino are very handy for debugging – you can put an LED and dropper resistor on them to sense levels, for example to confirm that the IRPS pulses are coming through.
        If you really get stuck, you’re welcome to email a hi-res photo of your assembly and I can cast my eye over it.

        1. Thanks for the prompt response and offer of help is all else fails.

          First out of the blocks, surely not! A hopeless kit maker is probably closer to the truth.

          I’ve got an old, old 50 MHz CRT analog scope. Will have to drag the it out of the wardrobe and hope it copes with the digital signals.

          I’m a novice at this sort of thing. PPA is the kick up the backside I needed to vastly improve my electronics knowledge and experience. I have a physics bachelor’s degree from long ago.

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