[In-depth analysis] Antminer S19 Pro

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To explore S19 Pro

When the test fixture LCD displays "ASIC NG: (0)", first measure the domain total voltage and the boost circuit 20V to make sure it is normal, then use the short-circuit probe to short the RO test point and the 1V8 test point between the first and second chips, and then run the chip search program. Look at the serial port log. If no chips are found at this time, it will be one of the following situations:

(1) Use a multimeter to measure the voltage of the 1V8 and 0V8 test points to see if they are 1.8V and 0.8V. If not, it may be that there is an abnormality in the 1.8V and 0.8V LDO circuits of this domain, or the two ASIC chips of this domain are not soldered well. Most of the time, it is caused by a short circuit of the 0.8V and 1.8V chip filter capacitors (measure the resistance of the chip filter capacitors on the front and back of the PCBA);

(2) Check whether the circuits of U2, U3 and U4 are abnormal, such as resistor solder joint failure, etc.

(3) Use a multimeter to measure the resistance of R232 or R233 to see if it is within 1 ohm and the reading does not jump randomly. If not, please replace the two resistors;

(4) Check whether the pins of the first chip are not soldered properly (this has been found during maintenance. When viewed from the side, there is tin on the pins, but when the chip is removed, it is found that the pins are not tinned at all).

If one chip can be found in step 1, it means that the first chip and the previous circuits are good. Use a similar method to check the following chips. For example, short-circuit the 1V8 test point and the RO test point between the 38th and 39th chips. If the log can find 38 chips, then the first 38 chips are fine. If 0 chips are still found, first check whether the 1V8 is normal. If it is normal, the chips after the 38th chip have problems. Continue to use the binary search method until the problematic chip is found. Assuming that the Nth chip has a problem, when the 1V8 and RO between the N-1th and Nth chips are short-circuited, the N-1 chip can be found, but when the 1V8 and RO between the Nth and N+1th chips are short-circuited, not all chips can be found.

When the test fixture LCD displays "ASIC 113: (reported 113)", it means that the computing board can detect 114 chips at 115200 baud rate, but only 113 chips are found at 12M baud rate, and one chip is not found at 12M baud rate.

Repair method: Use the binary method to short-circuit the 1V8 test point and the RO test point between the 38th and 39th chips through a short-circuit probe. If the log can find 38 chips, there is no problem with the first 38 chips. If 47 chips are short-circuited, the log reports 46 chips, which means that the 47th chip cannot be detected and there is no problem with the appearance inspection. Generally, the 47th chip can be replaced.

When the test fixture LCD displays "ASIC NG: (X, fixed report of a certain chip)", there are two situations:

(1) Case 1: The test time is almost the same as that of an OK board (usually the value of X does not change each time the test is performed) (the test time refers to the time from pressing the start test button to the LCD displaying the result "ASIC NG: (X)").

This situation is most likely caused by abnormal soldering of the front and rear CLK, CI, and BO series resistors of the Xth chip, so just focus on checking these six resistors. A small probability is that the following pins of the three chips X-1, X, and X+1 are soldered abnormally:

If you encounter a single board with low computing power, here is a convenient and quick method to locate and repair it. Log in to the IP address through Putty software to observe whether the domain operating voltage and NONCE return of the board are normal, and perform repairs based on the Putty log information.