Keeping your Antminer S19j in top condition can be a daunting task, but with the appropriate knowledge and tools, it is possible to maintain optimal performance. This guide offers comprehensive instructions on how to diagnose and resolve common issues that may arise while using the Antminer S19j. It will provide you with a step-by-step approach to performing routine checks, chip testing, signal flow verification, chip resoldering, and hash board testing with a tester. By following this guide, you can guarantee that your miner will continue to operate smoothly.
Preparation and Maintenance Guidelines
Proper preparation and maintenance of the Antminer S19j‘s components before, during, and after installation is crucial for optimal performance. This involves applying thermal gel to enhance heat transfer, creating air ducts to improve airflow, connecting power supplies in the correct sequence, preventing chip overheating, and ensuring that test fixtures meet production standards. Additionally, these guidelines should also provide instructions on how to clean components using approved solvents such as isopropyl alcohol or distilled water, as well as how to safely store components away from extreme temperatures and humidity levels. Lastly, regular maintenance checks should be performed every few months or at least annually to ensure that all system parts are functioning correctly.
Preparation Requirements for Repair Platform, Tools, and Equipment
I. Platform Requirements:
- To perform maintenance work, an anti-static maintenance workbench is required. It should be grounded, and an anti-static wristband and grounding are necessary.
II. Equipment Requirements:
- Constant temperature soldering iron (350°C-380°C) with a pointed tip for soldering small patches such as chip resistors and capacitors.
- Hot air guns and BGA rework stations are used for chip / BGA disassembly and welding.
- Multimeter with welded steel pins and heat-shrinkable sleeves for easy measurement. The recommended model is the Fluke 15b+ multimeter.
- Oscilloscope. The recommended model is UTD2102CEX+.
- A network cable is required for an internet connection and a stable network.
III. Test Tool Requirements:
- ARC Antminer Hashboard Tester
- Lab PSU 10-30V / 1-15A
- APW12 power supply: AP12_12V-15V_V1.2 and power adapter cable. It is recommended to use thick copper wire for the positive and negative poles of the power supply to connect the power supply and the power board and only limited to PT1 and maintenance test use.
- Use the test fixture of the V2.3 control board (test fixture material number ZJ0001000001). The positive and negative poles of the test jig need to be installed with discharge resistors. Using a cement resistance of 20 ohms and 100W or more is recommended.
IV. Maintenance Auxiliary Materials/Tools Requirements:
- Solder Paste 138°C, flux, Mechanic lead-free circuit board cleaner, and anhydrous alcohol.
- Mechanic lead-free circuit board cleaner cleans up the flux residue after maintenance.
- Thermally conductive gel is used to apply to the chip surface after repair.
- Ball-planting steel mesh, desoldering wick, and solder balls (the recommended ball diameter is 0.4mm).
- When replacing a new chip, it is necessary to tin the chip pins and then solder them to the hash board. Apply thermally conductive gel evenly on the chip’s surface, then lock the heatsink.
- Serial port code scanner.
- Serial port adapter board RS232 to TTL adapter board 3.3V.
- Self-made short-circuit probe (use the pins for wiring and welding and heat the shrinkable sleeve to prevent short-circuit between the probe and the small heatsink).
V. Common Maintenance Spare Material Requirements:
- 0402 resistor (0R, 051, 10K, 4.7K,)
- 0402 capacitor (0.1uF, 1uF)
- When replacing a chip, pay attention to the operation method. After replacing any component, check that the PCB board has no obvious deformation. Check the replacement and surrounding parts for missing parts, open circuits, and short circuits.
- Maintenance personnel must have electronic knowledge, at least one year of maintenance experience, and proficiency in BGA/QFN/LGA packaging and welding technology.
- After repair, the hashboard must be tested more than twice, and all tests must pass.
- Check the tools to ensure that the test fixture can work typically. Determine the parameters of the maintenance station test software, the version of the test jig, and other related parameters.
- To test repairing and replacing the chip, test the chip first and then do the functional test after it passes. The functional test must ensure that the small heatsink is welded correctly, the large heat sink is installed, and the thermal adhesive gel is applied evenly. When using the chassis to dissipate heat, two hash boards should be placed simultaneously to form an air duct. For single-sided testing in production, the air duct must also be formed.
- When measuring the signal, use fans to dissipate heat and ensure the fans are at full speed.
- When powering on the hashboard, connect the negative copper cord of the power supply first, then the positive copper cord of the power supply, and finally, insert the signal cable.
- When disassembling, reverse the order of installation. First, remove the signal cable, then pull the positive copper cord of the power supply, and finally, remove the negative copper cord of the power supply. If you do not follow this order, it may cause damage to U1 and U2.
- Before testing the pattern, the repaired hashboard must cool down before testing; otherwise, it will lead to testing NG.
- Pre-tin the chip pins with solder paste to replace a new chip and then solder them to the PCB for repair.
Overview of Antminer S19j Components
S19j Hashboard Structure
Check the PIC circuit by measuring the second pin of U6
Check the boost circuit output by measuring the voltage across C915
Check the output of each group of LDO 1.2V or PLL 0.8V by locating the components and measuring the voltage output
Check the chip signal output (CLK/CI/RI/BO/RST) by referring to the voltage value range and comparing with the adjacent group if there is a deviation
Troubleshoot specific issues such as LCD screen errors, incomplete chip detection, or low hash rate using appropriate methods
Perform routine inspection of the hash board for deformations, burnt marks, collision offset parts, or missing parts
Test the impedance of each voltage domain and ensure the voltage is around 0.32V
Use the test fixture to perform chip testing and locate the faulty chip through power supply sequence
Weld the chip again and add flux if necessary
Replace the BM1362 chip if the fault remains the same after re-soldering
Allow the repaired hash board to cool down before testing and judge it as a good product with more than two passes on the hash board tester