Testing the low voltage components

Let’s check that things are working correctly before we solder the costly high-voltage components.

Accessible test point for voltmeter / Ohmmeter probing
  • Note: with the revised BOM v1.2 rev1, the input power supply has been changed to 13.5V. The screenshots show +12V, but it can be +12V or +13.5V, depending on which BOM you are using.
  • With a multimeter, measure the input resistance of the +12V input; between GND and +12V (the bottom leg of switch S1), and make sure there is no short-circuits. The resistance will depend on the multimeter used and will likely be unstable, but it should be >10 kOhm.
  • Make sure that the power supply you are using is +12 V DC or +13.5V DC, depending on the BOM and that the positive terminal is on the inside of the barrel plug. Check a second time to make sure, as there is no overvoltage or reverse polarity protection on the board input.
  • Make sure that switch S1 is in position 0
  • Plug your power supply to the board. If all is going well, LED1 should be on (green). Make sure the plug is fully pressed into the jack. There is a first step with some resistance but you need to push it fully inside.
  • With a voltmeter, measure the following voltages with respect to GND (the picture above shows where they are accessible). Confirm that you have the correct voltages.
    • +12V
    • +5V (depending on BOM used and power supply used can be +4.5V, as long as >4V, you are good)
    • -5V (depending on BOM used and power supply used can be -4.5V, as long as <-4V, you are good)
    • +3.3V
  • If you skipped the communication test / initial configuration after soldering the SMT components, now is the time to do it. Part of the procedure include downloading the firmware to the micro-controller, and saving some important parameters in the EEPROM. If you have already performed these step, skip to the next test.

    Location of switches S1 and S2, and LEDs 1 (green), 2 (red), and 3 (blue)
  • Place switch S1 on the 1 position
  • Press switch S2 and keep it pressed. LED 2 (red) should turn on
  • Release switch S2. LED 2 should turn off and LED 3 (blue) should turn on
  • Put switch S1 back to position 0. LED2 and LED3 should be off
  • Remove power from the hvps-x

Next step

Is everything working up to now? If yes, let’s solder the high voltage components.

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