I. Required Tools
1. Electric screwdriver
2. Multimeter, ASIC Tester, Variable Bench PSU (0-25V/ 0-10A)
3. Soldering Station(hot air gun, soldering iron, hot plate)
4. ESD Protection (Tweezers, Mat, Wristband, Gloves)
5. Low Temperature Solder Paste
6. Fan Cooled Workstation & Fume Extractor
7. Chipquik Flux
8. PICKIT 3.5 or newer
The below table outlines some of the repair components necessary for repairs:
II. Miner Structure
The miner is composed of 3 hash boards, 1 control board, APW9 + power supply, and 4 cooling fans, as shown below:
III. Hashboard Structure
1. The hash board has a total of 65 BM1397 chips, and 13 voltage domains of 5 chips as shown below:
2. The power supply voltage for each board is 24.5V input. There are 13 voltage domains, and the voltage of every voltage domain is 1.8v.
3. Each domain has two LDOs with alternating 0.8 and 1.8V.
4. The boost circuit boosts 21V input to 24.5V
IV. Signal Transmission
1. The CLK-RST-BO-CO signal line is transmitted from the first chip to the 65th chip. RI signal is transmitted from the 65th chip to the first chip, as shown in following figure:
CLK (XIN) Signal is generated by Y1 25M crystal oscillator and transmitted from chip 01 to chip 65. Voltage measured by ground on dot and testing three other points. Other points measures 0.8V and 1.8V.
TX (CI, CO) Signal is input from pin 7 (3.3V) of IO port, transferred to IC U2 through level converter, then transmitted from chip 01 to chip 65. The voltage is 0V when the IO line is not inserted, and 1.8V during operation.
BO (BI, BO) Signal goes from chip 01 to chip 65. Voltage measured using multimeter is 0.01V.
RST Signal goes from pin 3 of the IO port, and then transmitted from chip 01 to chip 65. Voltage will be 0V without IO signal or in standby and 1.8V in operation.
RX (RI, RO) Signal goes from chip 65 to chip 01, return to pin 8 of the signal cable terminal via U1 and returned to the control board. The voltage is 0.3V when the IO line is not inserted, and the 1.8V during operation.
V. Using the Tester
1. First assure that the hash board is grounded and place it on the running fan base.
2. Connect the testers data cable to the control board. Then attach the negative(black) cable from the power supply to the hash board negative terminal. With the PSU powered off attach the positive(red) cable to the last terminal. Turn power supply on to 18.5V (Make sure the black is connected to the terminal closest to the data port, and red to the furthers).
3. Power on the tester and press begin test.
4. Result will may vary depending upon the ASIC tester you are using.
VI. Troubleshooting Phenomenon‘s
Phenomenon: 0 ASIC count on tester (PT1 / PT2 station type)
Step one: Check the power output first. Please check the circled part in Figure 5-1.
Step two: Check the voltage domain voltage output
The voltage in each voltage domain is about 1.6V. Generally, there is a domain voltage when power is supplied at 21V. It is preferred to measure the output of the power supply terminal of the hash board and determine whether the MOS is shorted (measure the resistance between pins 1, 4, and 8). If there is power supply at 21V but no domain voltage, continue to check downward.
Step three: check the PIC circuit
Measure whether the second pin of U3 has an output, the voltage is about 3.2V; if yes, please continue to troubleshoot, if there is no 3.3V, please check that the connection status of the fixture cable and the hash board is OK, and re-program the PIC.
PIC programming procedure:
1. Program the PIC program of the arithmetic board.
Download the programming tool: PICkit3; pin 1 of the PICkit3 cable corresponds to pin 1 of J3 on the PCB, and pins 1, 2, 3, 4, 5, and 6 need to be connected.
2. Programming software:
Open MPLAB IPE, select device: PIC16F1704, click power to select the power supply method, and then click operate. First step: select the file to find the .HEX file to be programmed. Second step: click connect to connect normally. Third step: click the program button, then click verify after finish. Prompt will be sent to prove that the programming is successful.
Step four: check the boost circuit output
Test D5 / D8 in chart 5-9 to measure 23-24.5V voltage.
Step five: check the LDO 1.8V or PLL 0.8V output of each group
Step six: Check the chip signal output (CLK / CI / RI / BO / RST)
Refer to the range of voltage values described by the signal direction. If the measurement encounters a large deviation in voltage value, it can be compared with the measured values of adjacent groups.
Assuming that the chip signal pin output voltage is normal, if the chip is still incomplete, for example, if 64 chips are detected, you can troubleshoot by shorting RO pull-up resistor R639. If 64 chips can be detected after shorting, it indicate that chips 1-64 should be normal, and you can troubleshoot the 65th chip at this time. If 63 chips are detected after short-circuiting, conduct troubleshooting forward; it is recommended to adopt the dichotomy method for troubleshooting, that is, test from the middle (starting from the 32th).
Troubleshooting comparison table:
2. Phenomenon: Single board detection chip is incomplete (PT1 / PT2 station)
Check the relevant signals (CLK / CI / RI / BO / RST) of the chip in front of and behind the error position, locate the bad position according to the IC with the abnormal signal measured, and refer to the signal direction and voltage range for repair.
3. Phenomenon: single board pattern NG, that is, the response nonce data is incomplete (PT2 station type)
The serial port is connected to the computer, and the computer reads the test log; according to the results displayed in the log, the chip position of insufficient nonce data can be determined; replace the chip at the corresponding position.
4. Phenomenon: Test temperature reading is abnormal (PT2 station)
Check the temperature-sensing power supply VDD and the connection status between the temperature-sensing and the chip (TEMP_P; TEMP_N), and check the soldering quality of the chip connected to the corresponding temperature-sensing.
Check the quality of the front and back chip heat sinks connected to the temperature sensor. If the heat sink is not welded well, it will affect the temperature difference.
VI. Problems Caused by Control Board Issues
1. The whole miner is not running
First step: check whether the voltages at several voltage output points are normal. You can disconnect U8 first if 3.3V short circuit. If the short circuit still exists, you can unplug the CPU for measurement. For other voltage abnormalities, replace the corresponding transformer IC in general.
Second step: if the voltage is normal, please check the welding status of DDR / CPU (X-RAY inspection on the production side).
Third step: try to update the flash program with the SD card.
2. The whole miner cannot find the IP
Probably the IP is not found due to abnormal operation. Refer to point 1 for troubleshooting. Check the appearance and soldering of the network port, network transformer T1, and CPU.
3. The whole miner cannot be upgraded
Check the appearance and soldering of the network port, network transformer T1, and CPU.
4. The whole miner fails to read the hash board or has fewer chains
A. Check the cable connection
B. Check the parts of corresponding chain on the control board
C. Check the wave soldering quality of the pins and the resistance around the plug-in interface
VII. Whole Miner Problems
1. Initial test of the whole miner
With reference to the test process documents, the general problems are assembly process issues and control board process issues.
Common phenomena: IP is not detected, the number of fans is abnormal, and the chain is abnormal.
2. The whole miner sweeping frequency band
Low hashrate caused by aging: Check the hashrate deviation of the corresponding hashboard to see if there is a large difference in hashrate, and take out the hashboard with a large hashrate deviation for test maintenance.
Check whether there’s low average hashrate caused by network interruption.
If there is a large temperature difference caused by hashrate then first check the aging environment. For the hashboard with high temperature, check the welding quality of the heat sink of the board and level of dust accumulation.
Aging miner protection: To avoid over-temperature protection of the boards, please control the aging environment temperature to be less than 40 degrees Celsius(104 °F).
If one of the chains cannot be detected, disassemble the miner and test the corresponding hashboard; if it is determined that the hash board is faulty, repair the hash board. Test the bus bars for 12v output voltage with a multimeter to determine whether the control board or PSU is faulty, then repair or replace them.
Refer to the above troubleshooting steps for each station. After repair, please use non-scanning mode to test PT2.
VIII. Other Matters Needing Attention
• Routine test: First perform visual inspection on the hash board to be repaired, observe whether the PCB is deformed or burnt. If yes, it must be handled first; check whether there are any parts with obvious burn marks, collision offset or missing parts, etc. If no problem is found through visual inspection, the impedance of each voltage domain can be tested first to detect whether there is a short circuit or an open circuit. If yes, it must be handled first. Check whether the voltage of each domain is about 1.5V.
• After the routine test is OK (in general, the short-circuit test is necessary for the routine test to prevent the chip or other materials from being burned due to short circuit when the power is on), you can use the hash board tester to perform chip detection, and determine the positioning based on the hash board tester test results.
• According to the display result of the test fixture test, test the voltages of chip test points (CO / NRST / RO / XIN / BI), VDD0V8 and VDD1V8, etc. starting from the vicinity of the faulty chip.
• According to the signal direction (the RX signal is passed in the reverse direction (from chip 65 to 1), and several signals CLK CO BO RST are transmitted in the forward direction (from chip 1 to 65). Find the abnormal fault point through the power supply sequence.
• When locating the faulty chip, the chip may need to be re-soldered. The method is to add aflux around the chip (preferably no-clean flux), and heat the solder joints of the chip pins to a dissolved status, so as to promote the chip pins and the pads to re-run, then removing tin finally, thus achieving the effect of re-tinning. If the failure is the same after re-soldering, the chip shall be replaced directly.
• The repaired hash board can be determined to be a good product if it passes the fixture tests for more than twice. For the first time, after the replacement of the accessories is complete, wait for the hash board to cool down and perform fixture test, after passing, set it aside and then cool it down; for the second time, wait for a few minutes until the hash board is completely cooled before testing.
• After the board is repaired, relevant maintenance / analysis records (requirements for maintenance reports: date, SN, PCB version, tag number, bad cause, bad liability attribution, etc.) should be prepared for feedback to production, after-sales, research and development departments.
• After the record is prepared, install the entire miner for conventional aging.
• Good products repaired at the production end should flow production from the first station of production (at least conduct the appearance inspection and start from the PT1 / PT2 test station)