Welcome to Peak Asic's S19 Pro Hashboard repair guide! We specialize in providing expert Antminer hashboard repairs, but we understand that some of you might want to try repairing your devices yourself. To support your efforts, we've created this comprehensive guide to help you through the process. Follow the steps below, and feel free to reach out to us if you need professional assistance or would like to send in miners for repair.

 1. Setting Up Your Repair Station

Platform and Tools

- **Workbench**: Get yourself an anti static repair workbench. Make sure it’s grounded, and wear an anti-static wristband.
- **Tools**: You'll need a constant temperature soldering iron (keep it between 350°-380°). A pointed tip is great for those tiny components. Also, have a hot air gun and a BGA rework station for those stubborn chips. A multimeter and an oscilloscope are must-haves too. Don’t forget a good network connection.
- **Power Supply**: Use an APW12 power supply (APW12_12V-15V_V1.2) with a custom power adapter cable. Thick copper wires are your best friend here.
- **Test Tools**: Make sure you have the V2.2010 control board test fixture. Discharge resistors of 25 ohms and above 100W are recommended.

Auxiliary Materials

- Solder Paste
- Flux (Thousand Pillars M705)
- Cleaning solvents like water and alcohol
- Thermal conductive gel (Fujipoly SPG-30B)

 Common Spare Parts

- **Resistors**: 0402 (0R, 51R, 10K, 4.7K)
- **Capacitors**: 0402 (0.1uf, 1uf)

 2. Repair Guidelines

1. **Chip Replacement**: Handle with care and ensure no PCB deformation. Check for open or short circuits after any replacement.
2. **Experience**: You should know your way around electronics and have at least a year of experience.
3. **Testing**: Test the board twice post-repair to ensure it’s good to go.
4. **Tools Check**: Ensure all tools and software are functioning correctly before starting.
5. **Thermal Management**: Always ensure proper heat dissipation during tests.

 3. Making and Using the Test Jig

1. **First Time Setup**: Use an SD card to update the fixture control board.
2. **Test SD Card**: Make sure the SD card is set up properly for single-sided heat sink inspection.
3. **Double-Sided Heat Sink Test**: Follow specific steps to ensure the SD card is configured correctly.

 4. Overview of the S19 Pro Structure

 Working Structure

- The board has 114 BM1398 chips, divided into 38 groups.
- Working voltage for each chip is 0.32V.
- Groups 33-32 are powered by a 20V boost circuit and output 1.8V to the LDO.
- Groups 31-1 get 12.6V from VDD, reduced by 0.32V at each step.

 Boost Circuit

- The boost circuit takes 12.6V and steps it up to 20V.

 Signal Flow

- **CLK (XIN)**: From Y1 25M crystal oscillator to chip 114 (0.7V-1.3V)
- **TX (CI CO)**: From IO port 7 through U4 to chip 114 (0V when idle, 1.8V during operation)
- **RX (RI RO)**: From chip 114 back to the control board via U2 (0.3V idle, 1.8V during operation)
- **BO (BI BO)**: From chip 1 to chip 114 (0V)
- **RST**: From IO port 3 through U3 to chip 114 (0V idle, 1.8V during operation)

 Full Machine Layout

- Composed of 3 computing boards, 1 control board, APW12 power supply, and 4 cooling fans.

5. Troubleshooting Common Issues

 Issue 1: Single Board Test Detects 0 Chips

1. **Check Power Output**: Verify the power output first.
2. **Voltage Domain Check**: Each domain should be around 0.32V.
3. **Check PIC Circuit**: Pin 2 of U6 should output 3.3V.
4. **Boost Circuit Output**: Check C69 for a 20V output.
5. **LDO Output**: Each LDO should output 1.8V or 0.8V.
6. Follow the RO Signal from the last chip to the first chip. If the voltage becomes abnormal replace the chip with the abnormal voltage.

 Issue 2: EEPROM NG on Fixture LCD

- Check U10 welding.
- Flash EEPROM

Issue 3: PIC Sensor NG

- Ensure correct welding of R217, R218, C22, and C23.
- Check the welding of U5, R216, R219, R220, U7, R221-R223, U8, R224-R226, U9, R229-R231.

 Issue 4: Incomplete Single Board Detection

- **LCD ASIC NG**: Follow specific steps to check the total voltage and boost circuit.

 Issue 5: Pattern NG on Single Board

- Usually caused by a significant difference in chip characteristics. Run PT2 test and replace bad chips.

 Additional Tips

- Always ensure chips are properly soldered and thermal gel is applied evenly.
- Follow the correct order when connecting and disconnecting power to avoid damaging components.

With this guide, you're all set to tackle those S19 Pro repairs like a pro. Remember, a little patience and precision go a long way. Happy repairing!