Antminer S9 hashboard showing up correct but with 0 hashrate

[Andartis]

Hello guys,

one of my S9 looks like this:
https://imgur.com/a/o3yagON
https://ibb.co/dxPLrz
That means everytging shows up normally, just the realtime hashrate for the board is 9.

Reflashed, rebooted, tried modded bmminer, cleaned the miner, checked all boards and switched cables and PSU.
One hashboard is just not hashing. Kernel shows it normally.

Any advice what I can do? I disconnected the board for now to reduce power by about 200w.

[tim-bc]

That board is faulty. You might have imbalanced voltage across domains. Basically, each hasboard on the Antminer S9 has 21 voltage domains (16 on S5+, 18 on S7 54, and 15 on S7 45) connected in series. Each domain contains 3 BM1387 chips, thus a single S9 hashboard has 63 BM1387 chips.

You need to get a multimeter and check the impedance at different test points. The circuit board has testing pins for CLK, CO, RI, BO, and RST signals located on both sides of the hashboard. After heatsinks are attached, these pins can only be reached with long, thin extensions to a multimeter’s test pins, such as needles. Be careful not to short circuit the signal by rubbing the needle against the side of the heatsink. You can check for voltage anomalies by checking the impedance on CLK and RST. The CLK signal transmits from chip 00 to 62 at 0.9V in standby and computing.

If you are sure there are no voltage anomalies across domains, first check on the RI signal and then the other signals at various points to find any anomalies. Test first at chip 32, then at chip 16/48, chip 8/24/40 etc. for max efficiency. Abnormal voltage can also result from anomalies in VDD1V8 (should be 1.8V) and VDD2V5 outputs. Lastly, you can check the C8 capacitor (upper left) to ensure voltage between 8.27V and 9.07V. If this voltage or the PIC voltage are abnormal, upgrade to the U3 PIC. Test U100 as well, to make sure it outputs 15V.

If you find a faulty chip and have a spare (either new or from a scrap board), you can remove the faulty chip(s) by adding flux paste to the pins at the edges of the chip, heating the chip until the solder dissolves, and removing the chip. Then, take a new chip, apply solder paste to it using the template, and heat the chip until the solder dissolves. Apply flux paste to the pins on the circuit board, align the chip correctly to ensure proper connections to each pin, then heat the chip and press down.

If you do end up replacing any chips, remember that all heatsinks near the malfunctioning chip(s) must be removed before conducting repairs to prevent PCB blistering, beginning with the smaller heatsinks. The small heatsinks on the front should be attached by heat only, while the larger heatsinks on the back must be attached with an evenly distributed amount of the black heat-conducting glue (#3461).

[Steamtyme]

When you say switched cables - Did you switch the ribbon cable from the hashboard to the control board? This could help identify if it is indeed the board or something else, possible the cable even.

Is this a new miner, used miner??

[Andartis]

That board is faulty. You might have imbalanced ...

Thanks for the description. I dont have the necessary hardware for doing this, although i would line to try to fix it for fun.

Is there anything "stupid" rather than cleaning and bending the board a bit here and there, I can do?

When you say switched cables - Did you switch the ribbon cable from the hashboard to the control board? This could help identify if it is indeed the board or something else, possible the cable even.

Is this a new miner, used miner??

It is a miner I got in return after repair. The old miner had 2 faulty boards. I got some compensation from bitmain for the failed repair. I dont want to send it in again since it hashes on 2 boards and shipping will be too expensive to be reasonable.

I switched the port and the cable. Its definitely the hashboard.

[tim-bc]

If you don't have the necessary hardware, you won't be able to fix it nor will it be any fun. Plus, you will not gain experience if you can't use the proper equipment. At the very least, make sure to set up a properly ventilated environment before attempting any heating or soldering.

The typical list of essential equipment includes:
1. SMD desoldering / rework station providing variably heated air up to 450+ degrees Celsius
2. Pointed soldering iron, with wire solder, BM1387 soldering template, and solder paste
3. APW3 or similar power source providing 12V DC with minimum 133A of potential output
4. Multimeter, tweezer, S9 hashboard tester connected to terminal with 115200 baudrate
5. MicroSDHC cards, razor knife, flux paste, black thermal glue #3461, anhydrous rubbing alcohol
6. Maintenance personnel with sound mastery of QFN encapsulation and soldering techniques

For any repair, you must have the SMD rework station, PSU, tweezer, and black thermal glue. For your specific repair, you will also want a multimeter, razor knife, flux paste, solder paste, and BM1387 soldering template.

[Steamtyme]

It is a miner I got in return after repair. The old miner had 2 faulty boards. I got some compensation from bitmain for the failed repair. I dont want to send it in again since it hashes on 2 boards and shipping will be too expensive to be reasonable.

I switched the port and the cable. Its definitely the hashboard.

Sucks to get an RMA back and still have the same issue, well half anyways.

Just running the 2 boards is definitely your best option right now. Any extra in shipping or specialty tools will just hurt your ROI now. Glad to hear they at least compensated you in some way.

You might be able to sell/donate the dead board for a couple bucks to someone who may want to salvage usable components. There's people looking in the marketplace from time to time.

[tim-bc]

You can always put the dead board in the middle and then overclock the other two to get you back to 12 TH/s.

[Andartis]

I overclocked the 2 boards to 12TH.

According to bitmain, they exchanged the miner. i think they just changed the serial number sticker. And thats where the desaster started. It was my first repair shipment with a whole miner. I had to pay import taxes again because the returned miner had another serial number. So it costed me about 225€ in total for the whole mess. 
I got a 220$ bitmain coupon. Wohoo.

[fanatic26_]

After heatsinks are attached, these pins can only be reached with long, thin extensions to a multimeter’s test pins, such as needles. Be careful not to short circuit the signal by rubbing the needle against the side of the heatsink.

As this is VERY easy to do, I would recommend you take some liquid electrical tape and cover the extension if it is not already protected. I coat mine and then just snip off the last quarter inch or so once dry. This will greatly help you in preventing shorts while testing

[Andartis]

What is the most linely diagnose, if suddenly after a reboot the hashboard hashed and then after another reboot showed agaon 0 hash?