Maintaining an Antminer S19+ mining rig can be a daunting task. Following the proper maintenance guide is essential to ensure that your mining rig runs efficiently and without interruption. This maintenance guide will provide step-by-step instructions for inspecting and repairing your Antminer S19+ and tips for troubleshooting any issues that may arise. It will also cover recommended practices for routine inspection, testing of hash boards, locating faulty chips, resoldering chips, and more. By following this guide closely, you can maximize the performance of your Antminer S19+ and keep it running smoothly.
Preparation and Maintenance Guidelines
It’s essential to take the time to properly prepare and maintain components before, during, and after installation. This includes applying thermal gel for better heat transfer, forming air ducts for better airflow, connecting power supplies in the correct sequence, fixing chips to prevent overheating, and ensuring test fixtures meet production requirements. Additionally, these guidelines should also include instructions on cleaning components with approved solvents such as isopropyl alcohol or distilled water, as well as how to store components away from extreme temperatures and humidity levels safely. Finally, regularly scheduled maintenance checks should be carried out every few months or at least annually to guarantee the proper functioning of all parts within the system.
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, 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, open, 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. Two hash boards should be placed simultaneously to form an air duct when using the chassis to dissipate heat. 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. 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 S19+ Components
S19+ Hashboard Structure
The S19+ hash board has 80 BM1398AC chips that are divided into ten domains, with each domain consisting of 8 ICs. The BM1398AC chip operates on a voltage range of 1.34V-1.4V. For the tenth domain, there are two groups of LDO for each 1.8V and 0.8V. The 14V output from the VDD_14V powers the 1.8V LDO and outputs 1.8V. The 1.8V output of this domain provides 0.8V via LDO. The ninth domain is powered by the VDD of the following domain and outputs 1.8V. There are three groups of 0.8V LDO for domains 1-9. The VDD of the following domain provides 0.8V via LDO. The voltage of each domain retreated is reduced by 1.38V.
Signal Direction of L7 Chip
The S19+ chip has four types of signals – CLK, TX, RX, BO, and RST – that flow in different directions between chips 01 and 80. Here’s a breakdown of the details for each signal:
- CLK: The CLK signal is generated by a 25M oscillator (Y1) and flows from chip 01 to chip 80. The voltage range is between 0.7V and 1.3V.
- TX: The TX signal flows from the IO port’s seven pins (3.3V) into IC U4 through level conversion, and then it’s transmitted from chip 01 to chip 80. The voltage is 0V when the IO signal is not inserted, and 1.8V during operation.
- RX: The RX signal flows from chip 80 to chip 01, returns to the signal cable terminal pin 8 through U2, and then back to the control board. The voltage is 0.3V when the IO signal is not inserted, and 1.8V during computing.
- BO: The BO signal flows from chip 01 to chip 80, and its voltage measures 0V with a Fluke 15B+ multimeter.
- RST: The RST signal flows from pin 3 of the IO port, and then it’s transmitted from chip 01 to chip 80. The voltage is 0V when no IO signal is inserted and the equipment is on standby, and 1.8V during computing.
In summary, the S19+ chip has five different signals that transmit in different directions and have varying voltage levels depending on whether or not the equipment is on standby or in operation.
Antminer L7 Structure
The entire miner consists of three hash boards, one control board, an APW12 power supply, and four cooling fans.
Identifying Common Issues with Hashboards and Troubleshooting Procedures
Phenomenon 1: The detection chip on a single hash board test shows 0
Check the voltage output of VDD_14V and the voltage domain. The voltage of each voltage domain should be around 1.34V-1.4V.
- If there is a 14V power supply, there should be a domain voltage.
- If there is no VDD_14V, check the output of PSU.
- If the output is normal, then check the PIC circuit (follow the below steps to check the PIC circuit).
- If 14V has a power supply but no domain voltage, continue to check.
To check the PIC circuit
- Measure whether there is an output on the eleventh pin of U4 and the voltage is around 3.3V.
- If there is, continue troubleshooting the problem.
- If there is no 3.3V, check the connection status of the hash board tester cable and whether the hash board is okay.
- Reprogram the PIC if needed.
- Refer to Figures 5-2, 5-3, 5-4, and 5-6.
Check the boost circuit output
- Measure the 14V voltage on D1.
Check the output of each group of LDO 1.8V or PLL 0.8V
- Check the output of each group of LDO 1.8V or PLL 0.8V
Check the chip signal output (CLK/CI/RI/BO/RST)
- Refer to the voltage value range described by the signal trend.
- If the measurement encounters a significant deviation of the voltage value, it can be compared with the measured value of the adjacent group to determine.
- PS: If the hash board is not powered or powered off according to the test sequence, causing R89, R90, U2, and U4 to burn out, the chip will report 0.
- When the EEPROM NG is displayed on the LCD screen of the hash board tester, check whether the welding of U10 is normal.
- If the PIC sensor NG is displayed on the LCD screen of the hash board tester, and the test read temperature is abnormal, follow the below steps to troubleshoot.
- Check whether the four resistors of R71~R77 are welded abnormally, and check whether the welding of PIN2, 3 of U4 is standard.
- Check whether the four temperature sensors U7, R78, R80, R81; U8, R83, R84, R88; U9, R92, R94, R95; U11, R96~R98, and the matching resistance welding are abnormal.
- The temperature sensor is located on the back of the PCB, while the resistance is on the front and back.
- Check the welding quality of the heat-sensitive chip and the small heat sink.
- The deformation of the large heat sink material will cause poor heat dissipation of the chip and affect the temperature difference.