# DAC Board: PCB Electrical Tests

This document outlines basic electrical tests to verify the AMDC DAC expansion board REV C, an accessory for the AMDC REV E. The expansion board <b> must not </b> be plugged into the AMDC while performing any electrical tests! Use an external power supply to verify the correct operation of board before connecting it to the AMDC.

## Electrical Shorts
1. Verify all pins on U12 have no shorts between adjacent pins

## Applying Power
> All power signals on the DAC board are isolated from the supplied power from the AMDC. To differentiate, this document will prefix all supply signals with SUPPLY_

The DAC expansion board signals, +/- 12V, +5V, and 0V, are generated from DC-to-DC converters U10 and U7. The DC-to-DC converters are each supplied with SUPPLY_5V and SUPPLY_GND to generate these signals. Apply the following voltages using an external power supply:

1. SUPPLY_5V must be applied to pin 1 on U7 and pin 2 on U10. 
2. SUPPLY_GND must be applied to pin 2 on U7 and pin 1 on U10.

> Pin 1 can be identified on both U7 and U10 by a square pad.

## Basic Voltage Tests
 1. Verify pin 1 on U12 is at 2.5V with respect to GND (C40 is connected to 2.5V and GND)
 2. Verify pin 7 on U12 is at 5V with respect to GND (C36 and C37 connect 5V to GND)
 3. Verify pin 3 on U8 is at +12V with respect to GND (C28 is connected to +12V and GND)
 4. Verify pin 3 on U9 is at -12V with respect to GND (C31 is connected to -12V and GND)
 5. Verify on power up all channel outputs are at 0V with respect to GND