Antminer S19j Pro Maintenance Guide

Maintaining an Antminer S19j Pro can be a challenging task, but with the right knowledge and tools, it is possible to keep your miner running at its peak performance. This guide provides comprehensive instructions on how to identify and fix common problems that may arise when operating the Antminer S19j Pro. It will provide step-by-step guidance for routine inspections, chip tests, signal flow checks, resoldering of chips, as well as testing of hash boards using a tester. With this guide in hand you’ll be able to ensure that your miner continues to operate 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 Kit

• ARC Antminer Hashboard Tester
• Lab PSU 10-30V / 1-15A

Bitmain Kit

• 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)

Maintenance Requirements

1. 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.
2. Maintenance personnel must have electronic knowledge, at least one year of maintenance experience, and proficiency in BGA/QFN/LGA packaging and welding technology.
3. After repair, the hashboard must be tested more than twice, and all tests must pass.
4. 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.
5. 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.
6. When measuring the signal, use fans to dissipate heat and ensure the fans are at full speed.
7. 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.
8. 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.
9. Before testing the pattern, the repaired hashboard must cool down before testing; otherwise, it will lead to testing NG.
10. 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 Pro Components

S19j Pro Hashboard Structure

The S19j Pro Hash Board contains 126 BM1362 chips, divided into 42 groups of 3 chips each. The operating voltage of the BM1362 chip used in the board is 0.32V. Seven groups (36th-42nd) are powered by the boost circuit U238, which provides LDO power for each group. The 35th group is supplied by VDD 15V, and 0.32V reduces the voltage of each domain.

 

Boost Circuit of the S19j Pro Hashboard

The boost circuit raises the voltage from the power supply (15V) to 20V.

 

 

Signal Trend of the S19j Pro Chip

• The CLK (XIN) signal is generated by the Y1 25M oscillator and flows from chip 00 to chip 125. Its voltage is 0.5V-0.6V.
• The TX (CI, CO) signal flows from IO port pin 7 (3.3V) to IC U4, and then from chip 01 to chip 126. Its voltage is 0V without the IO cable and 1.2V during operation.
• The RX (RI, RO) signal flows from chip 125 to chip 00 and returns to the control board. Its voltage is 0.3V without the IO cable and 1.2V during operation.
• The BO (BI, BO) signal flows from chip 00 to chip 125. Its voltage is 0V.
• The RST signal flows from pin 3 of the IO port to IC U1, and then from chip 00 to chip 125. Its voltage is 0V without the IO cable and 1.2V during operation.

 

Architecture of the S19j Pro Miner

The S19j Pro Miner consists of 3 Hash Boards, 1 Control Board, 1 Power Supply, and 4 Cooling Fans.

Identifying Common Issues with Hashboards and Troubleshooting Procedures

Phenomenon 1: Hashboard test detects 0 chip output

Check the power output

• Check power supply to hashboard for issues causing 0-chip output on testing station.
• Verify correct voltage output of power supply.
• Look for other issues such as short circuit in MOS.
• Address any problems found before proceeding to next steps in troubleshooting process.

 

Check the voltage output for each voltage domain

• Voltage domains have an approximate voltage of 0.32V.
• If using a 15V power supply, domain voltage should be present.
• Ensure proper functioning is to measure the output of the power supply terminal of the hash board.
• Check for any short circuits in the MOS by measuring the resistance between pins 1, 4, and 8.
• If the power supply has 15V but no domain voltage, further investigation is necessary.

 

Check the PIC circuit

• Measure whether there is output on the second pin of U6 and if the voltage is around 3.3V
• If there is output, continue troubleshooting
• If there is no 3.3V, check the connection status of the test fixture cable and the hash board, and reprogram the PIC

Check the boost circuit output

• Identify the boost circuit output components, including C915
• Use a multimeter to measure the voltage across C915
• The voltage across C915 should measure around 20V
• If the voltage across C915 is significantly lower than 20V or measures zero: The boost circuit may be faulty

 

 

Check the output of each group of LDO 1.2V or PLL 0.8V

• Locate the LDO or PLL components on the hash board PCB.
• Using a multimeter, set it to measure voltage and connect the negative lead to ground (GND) on the hash board.
• Using the positive lead, probe the output pin of the LDO or PLL that you want to check.
• Check the voltage reading on the multimeter. For LDO 1.2V, the voltage output should be around 1.2V. For PLL 0.8V, the voltage output should be around 0.8V.
• Repeat the process for each group of LDO 1.2V or PLL 0.8V on the hash board, checking the voltage output of each one.
• If the voltage output is outside the expected range, further troubleshooting may be required to determine the root cause of the issue.

 

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 large deviation of the voltage value, it can be compared with the measured value of the adjacent group to determine

 

More troubleshooting

• If the LCD screen of the test fixture displays “EEPROM NG,” check whether the welding of U10 is normal
• If the LCD screen displays “PIC sensor NG” and the tested temperature is abnormal, follow the steps below to troubleshoot: Check whether the four resistors of R217, R218, C22, and C23 are abnormally welded, and check whether the welding of PIN of U5 is normal
• Check whether the four temperature sensors of U5, R216, R219, R220, U7, R221R223, U8, R224R226, U9, R229~R231, and the matching resistance welding are abnormal
• The temperature sensors are all located on the back of the PCB, and the resistance is located on the front and back of the PCB
• Check whether the temperature sensor 3.3V power supply is normal
• Check the welding quality of the chip that connects the sensor and the small heat sink
• The deformation of the large heat sink material can cause poor chip heat dissipation, which affects the temperature difference.

 

Phenomenon 2: Single Hashboard Detection Chip is Incomplete

• When a single hash board detection chip is incomplete, the LCD may show “ASICNG” or “ASIC113” indicating that not all chips are detected. Here are the steps to identify and repair the problem.

LCD shows ASICNG

• If the LCD displays “ASICNG” with (0) next to it, the first step is to measure the total voltage of the measuring domain and the boost circuit to check if the 20V is normal. Then, use a short-circuit probe to short-circuit the RO test point and the 1V2 test point between the first and the second chip, and operate the program to find the chip. If no chip is found, there may be a problem with the LDO circuit or ASIC chips, or there may be a short circuit of 0.8V, 1.2V patch filter capacitors.
• If one chip can be found, use a similar method to check the next chips until the problematic chip is found.
• If the LCD displays “ASICNG” with (X) next to it, this indicates that a certain chip is fixedly reported. In the first case, the problem may be due to abnormal resistance welding of the front and rear CLK, CI, and BO of the Xth chip, or among the three chips, the following pins abnormal welding conditions of the chip occur. In the second case, the problem may be due to the chip not being soldered well.

LCD shows ASIC113

• If the LCD displays “ASIC113,” it means that the hash board can detect 114 chips at 115200 baud rate, but only 113 chips are found at 12M baud rate, and one chip could not be found at 12M baud rate. To repair this issue, use the dichotomy method to short-circuit the 1V2 test point and the RO test point between the 38th and 39th chips with the short-circuit probe. If the log can find 38 chips, there is no problem with the first 38 chips. If short-circuiting the 47th chip but the log reports 46th, it indicates that the 47th chip cannot be detected, and there is no problem with the visual inspection. Generally, the 47th chip should be replaced.
• In summary, the steps to identify and repair a single hash board detection chip that is incomplete include measuring voltages, short-circuiting test points, checking for abnormal resistance welding, and replacing problematic chips. The dichotomy method can be used to locate the problematic chip.

Phenomenon 3: Single hashboard Pattern NG, indicating that the nonce response data is incomplete (PT2 station)

• Significant differences between the characteristics of the chip and other chips cause pattern NG.
• The current solution is to replace the damaged chip.
• Replacement rules have been determined based on log information.
• If the appearance of the chip is not damaged, replace the chip with the lowest response rate in each domain.
• Domain and ASIC numbers start from 0.
• For example, if a test log shows that the response rate of chips ASIC [57], [58], [61], [63], and [64] is low, then the 61st (62nd) chip should be replaced.

Phenomenon 4: The chip test is OK, but the PT2 function test serial port does not stop (long – distance running)

• The repair method involves checking the serial port print log during the PT2 test.
• When the serial port starts to operate for a long time, a short-circuit probe is used to short-circuit RO&1.2V starting from the first chip.
• If the serial port stops long-term operating after the short circuit, the first chip is considered okay.
• The method involves finding the chip that still has a long-term operating failure after a certain chip is short-circuited.
• Generally, this failure is caused by a damaged chip, which should be replaced.

Phenomenon 5: PT1 chip test is OK, PT2 function test always reports a certain chip NG;

• The repair method involves checking the appearance of the chip and measuring the chip capacitor or resistance in front of it.
• Poor chip soldering, a damaged chip capacitor or resistor, or abnormal resistance are the most common causes of this problem.

Troubleshooting Common Miner Failures

• The failure phenomenon of the whole miner can have several common issues, including IP detection failure, abnormal fan display, less chain, abnormal temperature, incomplete chip detection, mining pool connection interruption, and low hash rate of one hash board.
• If the fan display is abnormal, the user should check if the fan is working normally, the connection with the control board is normal, and if the control board is abnormal.
• Less chain refers to a missing hash board. The user should check the connection between the hash board and the control board for an open circuit. If the connection is fine, the user can test the single board PT2 to check if it can pass the test. If it passes the test, it can be determined that the problem is on the control board, and if it fails, use the PT2 repair method to fix it.
• Abnormal temperature is usually due to high ambient temperature, causing the miner not to work correctly. The user should ensure that the PCB temperature set by the monitoring system does not exceed 90 degrees. If it does, the miner will alarm and fail to work normally. Abnormal fan operation can also cause an abnormal temperature.
• If the miner boots but has a hash rate of only 2/3 or 1/3 of the normal value, the user should test and repair the number of chips using PT2.
• If the connection to the mining pool is interrupted, the user should check the network connection.
• To observe the voltage domain and NONCE return of a hash board with low hash rate, the user can log in to the IP through Putty software and repair it based on the Putty log prompt.

Other Considerations and Maintenance Flow Chart

 

• Other matters needing attention involve maintenance flowchart for Antminer S19j Pro hash board repair.
• The maintenance flowchart involves several steps, starting with a routine inspection of the hash board. This includes visually inspecting the board for PCB deformation or scorching, checking for burnt marks on parts, collision offset parts, or missing parts. After the visual inspection, the impedance of each voltage domain should be tested to detect short circuits or open circuits. The voltage of each domain should be about 0.32V.
• Once the routine test is passed, the chip test can be performed using the test fixture. The positioning can be determined according to the test result of the test fixture. From the near-faulty chip, check the chip test points such as CO/NRST/RO/XIN/BI and voltages like VDD0V8 and VDD1V2.
• According to the signal flow, except for the RX signal, which is a reversely transmitted signal, several of the signals, including CLK CO BO RST, are forward transmission, and the abnormal fault point can be found through the power supply sequence.
• When locating the faulty chip, the chip needs to be welded again. Flux can be added around the chip and heated to a dissolved state to prompt the chip pins and pads to re-run in and collect the tin to achieve the effect of tinning again. If the fault remains the same after re-soldering, the BM1362 chip can be directly replaced.
• The repaired hash board can be judged as a good product with more than two passes when tested with the hash board tester. For the first time, after replacing the parts, the hash board should be allowed to cool down before testing. After passing the first test, set it aside and cool it down further for a few minutes before testing again for the second time.