Waching daily Nov 2 2018

We need to prepare these tools before the work

Antminer test fixture

Heat gun

Flux

Heat curing conduct heat black glue

Fluke 15B+ Multimeter

The negative pole of the test head of the multimeter needs to be welded with a sharp needle

Tweezers and scraping knife

High-temperature Tin solder paste

Circuit board cleaner

Tin tool

Now disassemble the miner

Install the USB driver

Install the Xshell5 program

Plug in the power but don't turn it on and connect to the computer USB

before we run the xshell program we need to make sure the USB driver is installed success

and remember the port number

Start the Xshell 5 program

Create a new connection

Protocol selection SERIAL

Configuring SERIAL protocol parameters

Port Select the port corresponding to USB. It was COM3 before. So I chose COM3 here.

Baud Rate selects 115200, then configures RLOGIN to 115200 too

Click to connect

Open the test fixture power switch

When you see this prompt, the connection is successful.

Plug in the cable and turn on the power of the hash board then put on the cooling fan.

Click the test button on the test fixture

If the "check chain asicNum = 57" appears on the XSHELL5 program screen

the signal is interrupted after it reaches the 57th chip.

It is likely that the 58th chip is damaged.

If the "check chain asicNum = 8" appears on the XSHELL5 program screen

the signal is interrupted after it reaches the 8th chip

It is likely that the 9th chip is damaged.

If the "check chain asicNum = 0" appears on the Xshell5 program screen

There are three problems:

NO.1: The test fixture does not detect the hash board

NO.2: The hash board power supply module has failed.

NO.3: The 0th chip or the 62nd chip has failed.

If the Xshell5 program screen appears this prompt, it means that the hash board is working fine.

Now let's determine if the 58th and 9th chips detected by the test fixture are damaged:

Test the resistance value

the multimeter uses the diode gear position

Test voltage, multimeter uses DC gear position

The resistance and voltage values were tested by these five test points.

The following are normal chip voltage values and resistance values

which are normally floating at around 20%.

Note that the internal and external parameters are different.

Mark the damaged chip.

Adjust the heat gun temperature to 450 degrees Celsius

The distance between the heat gun and the heat sink is kept at 1 cm.

After heating it for 10 seconds, remove the heat sink.

After heating the back side for 10 seconds, remove it with force.

Heat the chip and remove it after about 10 seconds

Place the new chip on the Tin tool and add tin to it.

Keep the heat gun at 10 cm or more to heat the tin solder paste until it melts.

Place the chip alignment position into the hash board.

Heat the surface of the chip for 10 seconds.

Ensure chip pin alignment

Then test the hash board again

Now the hash board is normal.

Heat the front heat sink and install it.

Apply the black glue to the surface of the chip before installing the back heat sink.

Antminer S9 hash board repair completed

The following is a hash board signal diagram and notes:

Use the multimeter's negative electrode needle for detection

The Test needle cannot be in contact with the heat sink

Signal transmission direction