Welcome to Peak Asic's S19 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. Preparation for Maintenance
**Platform Requirements:**
- You need an anti static maintenance workbench. Ground the workbench and wear an anti-static wristband, making sure it’s also grounded.
**Equipment Requirements:**
- **Soldering Iron:** Use a constant temperature soldering iron (set between 350-380 degrees). A pointed tip is best for small components like chip resistors and capacitors.
- **Heat Gun and BGA Rework Station:** For removing and soldering chips/BGAs.
- **Multimeter:** Make sure it’s reliable; Fluke is recommended. Add welded steel needles and heat-shrink sleeves to simplify measurements.
- **Oscilloscope:** Agilent is recommended.
- **Network Cable:** Ensure it's stable and internet-connected.
**Test Tools:**
- **APW12 Power Supply:** With a self-made power adapter cable. Use thick copper wires (4AWG, less than 60cm long) for the positive and negative poles to connect the power supply and hashboard.
- **Test Fixture:** Use the V2.2010 control board’s test fixture. Install a discharge resistor (recommended: 25 ohms, 100W cement resistor) on the power supply's positive and negative poles.
**Auxiliary Materials/Tools:**
- **Solder Paste:** Qianzhu M705.
- **Flux, Board Washing Water, and Absolute Alcohol:** For cleaning flux residues after maintenance.
- **Thermal Conductive Gel:** Fujipoly SPG-30B for applying on the chip surface after maintenance.
- **Other Tools:** Ball planting stencil, tin suction wire, solder ball (0.4mm diameter), code scanning gun, port adapter board RS232/TTL adapter board 3.3V, and a self-made short-circuit probe.
**Common Maintenance Spare Materials:**
- **Resistors:** 0402 resistors (0R, 51R, 10K, 4.7K).
- **Capacitors:** 0402 capacitors (0.1uf, 1uf).
2. Maintenance Procedures
**1. Chip Replacement:**
- Be cautious while replacing chips. After replacing, check for any deformations or open/short circuits in the PCB and surrounding areas.
**2. Skill Requirements:**
- Maintenance personnel should have solid electronics knowledge, over a year of maintenance experience, and proficiency in BGA/QFN/LGA packaging and soldering.
**3. Testing:**
- Ensure the computing board passes at least two tests before considering it fixed.
**4. Tool and Fixture Check:**
- Verify the functionality of tools and fixtures, set parameters for the maintenance station test software, and confirm the test fixture version.
**5. Chip Maintenance and Replacement Testing:**
- First, detect the chip, then perform functional tests ensuring the small heat sink is properly soldered. When installing a large heat sink, evenly apply thermal gel on the chip's surface, and run the cooling fan at full speed using the chassis for heat dissipation. Place two computing boards simultaneously to form an air duct.
**6. Signal Measurement:**
- Use 4 cooling fans at full speed while measuring signals.
**7. Powering On/Off Hashboard:**
- When powering on, connect the negative copper wire first, then the positive, and finally the signal cable. When powering off, reverse the order: signal cable first, then positive copper wire, and lastly the negative. Not following this order may damage components like R8, R9, U1, and U2.
**8. New Chip Replacement:**
- Pre-tin the chip pins and solder paste before attaching the chip to the PCBA.
3. Fixture Making and Important Points
- Ensure the fixture supports adequate heat dissipation for the computing board and facilitates signal measurement.
- Update the FPGA control board of the fixture using a 19 series test fixture SD card. Insert the SD card into the slot and power on for 1-3 minutes until the indicator light flashes 3 times, signaling the update completion.
- Make SD cards according to requirements for single-sided heat sink inspection chips and double-sided heat sink 8 times Pattern tests.
4. Principle Overview
**1. S19 Computing Board Structure:**
- Comprises 76 BM1398 chips in 38 groups, each with 2 ICs.
- The working voltage for the BM1398 chips is 0.36V.
**2. Boost Circuit:**
- Converts 14V to 19V as shown in figure references.
**3. Chip Signal Flow:**
- **CLK (XIN) Signal:** From Y1 25M crystal oscillator to chip 76.
- **TX (CI, CO) Signal:** From IO port pin 7 to chip 76.
- **RX (RI, RO) Signal:** From chip 76 back to the control board.
- **BO (BI, BO) Signal:** From chip 01 to chip 76.
- **RST Signal:** From IO port pin 3 to chip 76.
**4. Machine Structure:**
- Consists of 3 computing boards, 1 control board, APW12 power supply, and 4 cooling fans.
5. Common Malfunctions and Troubleshooting
**1. Chip Detection Failure:**
- Check power output, voltage domains, and the PIC circuit.
- Measure the second pin of U3 for a 3.3V output.
- Program the PIC if needed using PICkit3 and MPLAB IPE.
-If the pic does not work the board will have no power running to it.
**2. Voltage and Signal Issues:**
- Measure C55 for 19V output.
- Check each group of LDO 1.8V or PLL 0.8V outputs.
- Verify chip signal outputs (CLK/CI/RI/BO/RST).
**3. Incomplete Board Detection:**
- Measure domain voltages and check for abnormal welding or short circuits.
- Use short-circuit probes to identify problematic chips by comparing voltage readings.
Remember, the success of these procedures hinges on attention to detail and careful handling of each component. So gear up, follow these steps, and keep those machines running smoothly!