Quote from: NotFuzzyWarm on October 10, 2017, 02:57:11 AM

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I'd like to learn to fix these myself, is there a good thread around here that covers most issues with these boards?

There is ZERO info as to what typically goes wrong. I too would give my eye-teeth to get a handle on it. The only general symptom usually is the Vcore regulator shutting down (red LED light on board near the PCIE sockets not lit). As to *why* -- unknown. Either the regulator itself fails or a chip or bypass cap shorts out shutting it down.

This is ALL based on the S7 stuff, so take it with a grain or 100 of salt.

I don't believe that, if the s9 is the same, the LED is the regulator. In the S7, the two LEDs are attached to the last chip in the chain's busy / ready lines. These indicate (along with the correct power draw) that at least some data is getting to the end chip. It does *not* mean that the hashes from the chips (or anything, really) is getting back.

I don't have any S9 boards to play with, but on the S7 you can check the 14.5v boost converter, which is (due to it being the coldest part on the board) subject to condensation. It's really easy to replace with an ebay special. I have heard people saying that this boost is only to support the end of the chain, but it doesn't seem to - the whole IO chain goes close to 0v if it's not outputting.

In terms of the IO regulation, the 14.5v is split over the entire board (3 chip sections) by a resistive divider. This then feeds the approximate IO voltages into linear regulators, which referenced to the ground on each chip appear to provide the *return* (downstream) IO voltage.

Easiest diagnostics to do on the S7s is to play follow the clock. You'll need a scope for that and it's an art rather than a science - sometimes, trouble later on down the chain will disrupt the startup of the first chip, so nothing is seen consistently anywhere.

No detection but I2C works - shows as 48 ASICs and shows 'timeouts' on the syslog page. Temps are shown. CAN sometimes mine in this situation but be careful - the section of the chain that is not getting results back seems to overheat (I guess it only gets fed a new block to work on when the rest of the string does and busy-waits till then)

Nothing at all - no I2C so can't detect a board is there

If someone would like to donate a S9 control board and a dead S9 board, I'll have a look, but I can't afford to do anything which costs money right now.

Good luck!

Cheers,

Allan.