2 out of 3 S9s are slowing down.

[freak1]

Hello.

Over the past few days 2 af my 3 my S9s has started acting strange. (been running fine for 4+ months) They start to mine slower after running some time, sometimes its hours sometimes minutes.

I tried resetting them and also updated to latest firmware Antminer-S9-all-201704270135-autofreq-user-Update2UBI-NF.tar.gz.

There is no known problems from bitmain that fits my problem. no ASCI errors, fans are running and all.

one is 14T one is 13T model, i have another 13T that runs fine also upgraded to the same firmware.

How do i make sure i used the right firmware and should have used the one with fixed freq? What am i missing?


https://ibb.co/eJrK9Q

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[achmir]

do u have warranty?

[nb1985]

How are the fans doing on the 2 that have slowed?

[philipma1957]

they get dust filled have you cleaned them?

[nb1985]

Also, have you confirmed that the issue isn't with the power supply?

[freak1]

I only cleaned it with air with the fans still in place, maybe i should remove the fans first?

I bought them on alibaba so not sure on the warenty.

Fans are all doing fine, about the same as the working also the temps.

The power supply is the original bitmain so i dont think they are bad.

[AtraxPool]

Get a airline or some compressed air and give them a good blast out make sure there is no dust on the boards.
It may also be a PSU issue that is causing lower hashrate you should monitor the psu draw with a meter to check the draw see is there is any issues there.

I would hold off re-flashing them as this can be risky you should have a warrenty for the boards if there is a issue with them.