Antminer S19 Maintenance & Repair Guide

Maintaining an Antminer S19 can be a daunting task if you don’t know what to look for. Knowing the basic steps of maintenance and troubleshooting is essential in keeping your miner running smoothly and efficiently. In this guide, we will cover the basics of Antminer S19 maintenance, from routine inspections to testing hash boards and replacing faulty chips. We will also provide tips on how to use Putty software to diagnose problems with the NONCE response status and domain voltage levels. With this guide, you’ll have all the information needed to keep your Antminer S19 running at optimal performance.

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, 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, open, 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. 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.
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. 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 S19 Components

S19 Hashboard Structure

The S19 hash board is made up of 76 BM1398 chips, which are divided into 38 groups (domains). Each group consists of 2 ICs, and the operating voltage of the BM1398 chip used in the S19 hash board is 0.36V. For the 38th, 37th, 36th, 35th, 34th, 33rd, and 32nd groups (a total of 7 groups), LDO is powered by the 19V output from the boost circuit U9 and outputs 1.8V. The 30th group to the 1st group are supplied by VDD13.64V through the LDO to provide 1.8V, and the voltage of each domain is reduced by 0.36V. All 0.8V is provided by the 1.8V output of this domain via LDO.

 

 

S19 Hashboard Boost Circuit

The boost circuit transfers the 14V power supplied by the power supply to 19V

 

Signal Trend of S19 Chip

The S19 chip has several signal trends:

• The CLK (XIN) signal is generated by Y1 25M oscillator and transmitted from chip 01 to chip 76, with a voltage of 0.7V-1.3V.
• The TX (CI, CO) signal is transmitted from IO port 7 pin (3.3V) into IC U2 through level conversion, and then transmitted from chip 01 to chip 76. The voltage is 0V when the IO signal is not inserted, and the voltage is 1.8V during operation.
• The RX (RI, RO) signal is transmitted from chip 76 to chip 01, returns to the signal cable terminal pin 8 through U1, and then returns to the control board. The voltage is 0.3V when the IO signal is not inserted, and the voltage will be 1.8V during computing.
• The BO (BI, BO) signal is transmitted from chip 01 to chip 76, with a multimeter measurement value of 0V.
• The RST signal is transmitted from pin 3 of the IO port, and then from chip 01 to chip 76. If no IO signal is inserted and the equipment is in standby, the voltage is 0V, and 1.8V when computing.

Whole Miner Architecture:

The whole miner consists of 3 hash boards, 1 control board, APW12 power supply, and 4 cooling fans.

Identifying Common Issues with Hashboards and Troubleshooting Procedures

Phenomenon 1: The detection chip on a single hash board test shows 0

The hash board is an important component of a cryptocurrency mining machine. If it is not functioning properly, it can cause serious problems. This article aims to provide troubleshooting steps for common faults related to the hash board.

Check the power output of the hashboard

• Check the power output of the hashboard.
• If the power output is abnormal, troubleshoot the issue using the following steps.
• Check the input voltage of the hash board and ensure that it is normal.
• Check the input voltage of the power module and ensure that it is normal.
• Check whether the input voltage is outputting from the power module.
• Check the MOS tube’s resistance and ensure it is not short-circuited.
• If the MOS tube is short-circuited, replace it with a new one.
• Check the output voltage of the power module and ensure that it is normal.
• Check the output voltage of the hash board and ensure that it is normal.
• If the voltage is abnormal, troubleshoot the issue using the next step.

Check the voltage output in the voltage domain

• Check the voltage output in the voltage domain.
• The voltage of each voltage domain should be about 0.36V.
• Check whether there is a 14V power supply, which should generally have a domain voltage.
• Measure the output of the power supply terminal of the hash board.
• Check whether the MOS is short-circuited by measuring the resistance between pins 1, 4, and 8.
• If the MOS is short-circuited, replace it with a new one.
• If there is a 14V power supply but no domain voltage, continue to troubleshoot using the next step.

 

Check the PIC circuit

• Check the PIC circuit.
• Measure whether there is output on the second pin of U3.
• Ensure that the voltage is about 3.3V.
• If there is output and the voltage is normal, continue to troubleshoot the issue.
• If there is no 3.3V output, check the connection status of the hash board tester cable and the hash board.
• Reprogram the PIC if necessary.

Check the boost circuit output

• Check the boost circuit output.
• Locate C55 and measure the voltage.
• The voltage should measure 19V.
• If the voltage is abnormal, troubleshoot the issue using the next step.

 

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.
• Ensure that the voltage output is normal.
• If the voltage output is abnormal, troubleshoot the issue using the next step.

Check the chip signal output (CLK/CI/RI/BO/RST)

• Check the chip signal output (CLK/CI/RI/BO/RST).
• Refer to the voltage value range described by the signal trend.
• If the voltage value has a large deviation, compare it with the measured value of the adjacent group to determine the issue.
• If the hash board is not powered or powered off according to the test sequence, causing R8, R9, U1, and U2 to burn out, the chip will report 0.
• If the EEPROM NG is displayed on the LCD screen of the hash board tester, check whether the welding of U5 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, then follow the next steps to troubleshoot the issue.
• Check whether the four resistors of R24~R27 are welding abnormally and check whether the welding of PIN2, 3 of U3 is normal.
• Check whether the four temperature senses U4, R28R30, U6, R31R33, U7, R34R36, U8, R37R39 and the matching resistance welding are abnormal.
• Check the location of the temperature sensor. The temperature sensor is all located on the back of the PCB, while the resistance is located on the front of the PCB.
• Check whether the temperature-sensitive 3.3V power supply is normal.
• Check the welding quality of the heat-sensitive chip and the small heat sink.
• If the large heat sink material is deformed, it can cause poor heat dissipation of the chip and affect the temperature difference.

 

Phenomenon 2: Single board detection chip is not complete

• Check the LCD display ASICNG by measuring the total voltage of the measuring domain and boost circuit.
• If the chip is not found, check for possible issues like abnormal voltage at the 1V8 and 0V8 test points, issues with the U1 and U2 circuits, resistance of R8 or R9, and whether the pins of the first chip are soldered well.
• If one chip is found, check the subsequent chips using a similar method and short-circuiting the 1V8 test point and the RO test point between the 38th and 39th chips to locate the problematic chip.
• For the LCD display ASIC75, short-circuit the 1V8 test point and the RO test point between the 38th and 39th chips. If short-circuiting 47 chips, but the log reports 46, it indicates that the 47th chip cannot be detected, and the 47th chip needs to be replaced.
• In the case of a certain chip being fixed, check for abnormal resistance welding of the front and rear CLK, CI, and BO of the Xth chip. If the test time is almost twice as long as the good board, it may indicate a problem with soldering. Directly measure the domain voltage to locate the problematic domain, or use the 1V8 and RO short-circuit method to locate the abnormal position.

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

• PatternNG is a problem that occurs due to significant differences in the characteristics of a particular chip compared to other chips. To resolve this issue, it has been identified that the chip’s die is damaged and needs to be replaced.
• Based on the log information, the following rules have been established for replacing the chip:
• If the chip’s appearance is not damaged, the chip with the lowest response rate in each domain should be replaced.
• In case multiple chips in the same domain have a low response rate, the one with the lower nonce in that domain should be replaced.
• To illustrate, consider the following test log which shows that the response rate of four chips (asic[36], asic[37], asic[43], asic[75]) is low. Since asic[36] and asic[37] are in the same domain, the one with the lower nonce between them should be replaced. Similarly, both asic[43] and asic[75] should also be replaced.
• It is important to note that the domain and asic numbers start from 0.

Phenomenon 4: Check that chip test is OK, PT2 function test serial port does not stop (long-distance running)

The method for repairing the issue is as follows: during the PT2 test, closely monitor the serial port print log. When the serial port has been operating for an extended period of time, use a short-circuit probe to short-circuit RO and 1.8V starting from the first chip. If the serial port stops long-term operation after the short circuit, the first chip is functioning properly.

Continue this process and short-circuit the following chips one by one until a chip is found that still causes long-term operating failure even after being short-circuited. This failure is usually due to damage to that particular chip, and so it should be replaced.

In summary, this repair method involves checking each chip in sequence by short-circuiting them and monitoring the serial port operation until the faulty chip is identified and replaced.

Phenomenon: PT1 chip test is OK, PT2 function test always reports a specific chip NG.

• Check the appearance of the chip.
• Measure the chip capacitor or resistance in front of the chip.
• Poor chip soldering or damage to the chip capacitor or resistor, or abnormal resistance usually causes the issue.

In summary, to repair the issue, one should first inspect the chip’s appearance and then measure the capacitor or resistance in front of it. The issue is typically caused by poor chip soldering or damage to the chip capacitor or resistor, which results in abnormal resistance.

Troubleshooting Common Miner Failures

Preliminary test of the whole machine

Referring to the test process document, the general problems that arise are assembly process problems and control board process problems. Common problems include the inability to detect the IP, abnormal number of detected fans, and abnormal detected chain. If any issues arise during the test, they should be repaired according to the monitoring interface and the test LOG prompts. The maintenance methods for the initial test and the aging test of the whole machine are the same.

Aging Testing of the Miner

The aging test should be repaired according to the monitored interface test. For instance:

• Abnormal fan display: In such cases, we need to check whether the fan works normally, whether the connection with the control board is normal, and whether the control board is abnormal.
• Less chain: This means that three boards are missing one board. In most cases, there is a problem with the connection between the hash and control boards. Check the cable to see if there is an open circuit. If the connection is OK, you can test the board to PT2 to see if it can be tested. If it can be tested, it can basically be determined that it is the control board. If the test fails, use the repair method of PT2 maintenance.
• Abnormal temperature: Generally, the temperature is high. The maximum PCB temperature set by our monitoring system cannot exceed 90℃. The fan will alarm and it will not work normally. Generally, the ambient temperature is too high, and the abnormal operation of the fan will also cause abnormal temperature.
• Insufficient number of chips: If the number of chips is insufficient, you can refer to PT2 for testing and repair.
• After running for a period of time, there is no hashrate, and the connection of the mining pool is interrupted, check the network.

If the miner still loses hashrate, reduce the frequency and other conditions remain unchanged. Let the miner mine to see if it will lose hashrate and whether the hash board will hit X. If it still hits X in losing hashrate, then remove the heat sink of the hashboard for mining and wait for the hashrate to drop. Measure whether the domain voltage is normal. Generally, the domain voltage will be abnormal in the problematic domain. Then measure the RI signal to see if the RI signal is broken. If the RI signal is missing, basically, the chip is short-circuited or damaged after being tinned.

Other Considerations and Maintenance Flow Chart

The repair process for the hash board can be broken down into several steps:

Routine Inspection

• Visually inspect the hash board for deformations, scorching, burnt marks, offset parts, and missing parts.
• Test the impedance of each voltage domain to detect short circuits or open circuits.
• Check whether the voltage of each domain is about 0.36V.
• Chip Test:
• Perform a routine test to avoid short circuits when power is turned on.
• Test the chip using a hash board tester.
• Determine the location of the fault using the test results of the hash board tester.
• Check the chip test points and voltages such as VDD0V8 and VDD1V8 according to the signal flow.

Fault Localization

• Reverse transmit the signal from chip No. 76 to No. 1, except for the RX signal, to locate the abnormal fault point through the power supply sequence.
• When the faulty chip is located, weld the chip again by adding flux around the chip and heating the solder joints of the chip pins to a dissolved state. This will prompt the chip pins and pads to re-run in and collect the tin, achieving the effect of tinning again.
• If the fault remains the same after re-soldering, replace the chip directly.

Testing and Verification

• The repaired hash board can be judged as a good product with more than two passes when tested with the hash board tester.
• After replacing the parts, wait for the hash board to cool down and use the hash board tester to test. Once the test is passed, set it aside and cool it down.
• After a few minutes, test the hash board again when it cools down.
• To summarize, the repair process for the hash board involves routine inspection, chip test, fault localization, and testing and verification. Through these steps, the faulty chip can be located and repaired or replaced, and the hash board can be tested to ensure it is functioning properly.